feat(ui): add reusable json-file-manager widget for plugin file management

Introduces JsonFileManager — a zero-CDN, keyboard-accessible, configurable
widget for managing JSON data files from plugin configuration forms.

web_interface/static/v3/js/widgets/json-file-manager.js (new):
- Self-contained class with scoped CSS (no global leakage)
- File list with cards: enable/disable toggle, entry count, size, date
- Drag-and-drop + click-to-browse JSON upload
- Textarea-based JSON editor (no CDN); Format + Validate buttons
- Ctrl+S to save, Escape to close any open modal
- Create-new-file modal with configurable fields and validation
- Delete confirmation modal
- All actions (list/get/save/upload/delete/create/toggle) are configurable
  via x-widget-config in config_schema.json — no plugin-ID hardcoding

web_interface/static/v3/plugins_manager.js:
- New handler for x-widget: "json-file-manager" — renders mount div,
  instantiates JsonFileManager with x-widget-config and plugin ID

web_interface/templates/v3/base.html:
- Include json-file-manager.js (defer) before plugins_manager.js

Usage: set x-widget: "json-file-manager" + x-widget-config in any
plugin's config_schema.json (see ledmatrix-plugins of-the-day for a
complete example).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/wifi_manager.py

@@ -150,6 +150,18 @@ class WiFiManager:
         logger.info(f"WiFi Manager initialized - nmcli: {self.has_nmcli}, iwlist: {self.has_iwlist}, "
                    f"hostapd: {self.has_hostapd}, dnsmasq: {self.has_dnsmasq}, "
                    f"interface: {self._wifi_interface}, trixie: {self._is_trixie}")
+
+        # Once per process: remove a stale force-AP flag left by a prior crash.
+        # Guard with a class-level flag so the nmcli AP-state check only runs
+        # once even though WiFiManager is instantiated per-request.
+        if not WiFiManager._startup_cleanup_done:
+            WiFiManager._startup_cleanup_done = True
+            if self._FORCE_AP_FLAG_PATH.exists() and not self._is_ap_mode_active():
+                try:
+                    self._FORCE_AP_FLAG_PATH.unlink(missing_ok=True)
+                    logger.debug("Removed stale force-AP flag on startup (AP not active)")
+                except OSError as exc:
+                    logger.warning(f"Could not remove stale force-AP flag: {exc}")
     
     def _show_led_message(self, message: str, duration: int = 5):
         """
@@ -474,7 +486,10 @@ class WiFiManager:
                 if result.returncode == 0:
                     for line in result.stdout.strip().split('\n'):
                         if '/' in line:
-                            ip_address = line.split('/')[0].strip()
+                            # nmcli -t output is "IP4.ADDRESS[1]:x.x.x.x/prefix";
+                            # bare "x.x.x.x/prefix" is also accepted defensively.
+                            _, sep, rest = line.partition(':')
+                            ip_address = (rest if sep else line).split('/')[0].strip()
                             break
                 
                 # Final fallback: Get signal strength by matching SSID in WiFi list
@@ -500,6 +515,13 @@ class WiFiManager:
             
             # Check if AP mode is active
             ap_active = self._is_ap_mode_active()
+            # wlan0 shows as "connected" in AP mode; clear client-station fields so
+            # callers don't mistake the AP for an outbound WiFi connection.
+            if ap_active and wifi_connected:
+                wifi_connected = False
+                ssid = None
+                ip_address = None
+                logger.debug(f"{wlan_device} is in AP mode — overriding wifi_connected to False")
             
             return WiFiStatus(
                 connected=wifi_connected,
@@ -690,6 +712,10 @@ class WiFiManager:
     # ---------------------------------------------------------------------------
 
     _IP_FORWARD_SAVE_PATH = Path("/tmp/ledmatrix_ip_forward_saved")  # nosec B108 - process-specific named file; device is single-user RPi
+    # Written when AP mode is manually force-enabled; prevents daemon auto-disable
+    _FORCE_AP_FLAG_PATH = Path("/tmp/ledmatrix_force_ap_active")  # nosec B108 - process-specific named file; device is single-user RPi
+    # Ensures the startup stale-flag cleanup runs once per process, not per instantiation
+    _startup_cleanup_done: bool = False
 
     def _validate_ap_config(self) -> Tuple[str, int]:
         """Return a sanitized (ssid, channel) pair from config, falling back to defaults."""
@@ -1367,7 +1393,7 @@ class WiFiManager:
                         logger.error(f"Failed to restore original connection: {original_ssid}")
                         # Trigger AP mode as last resort
                         self._show_led_message("Enabling AP mode...", duration=5)
-                        ap_success, ap_msg = self.enable_ap_mode()
+                        ap_success, ap_msg = self.enable_ap_mode(force=True)
                         if ap_success:
                             logger.info("AP mode enabled as failsafe")
                             return False, "Connection failed and restoration failed. AP mode enabled."
@@ -1379,7 +1405,7 @@ class WiFiManager:
                 elif not success:
                     logger.warning(f"Connection to {ssid} failed and no original connection to restore")
                     self._show_led_message("Enabling AP mode...", duration=5)
-                    ap_success, ap_msg = self.enable_ap_mode()
+                    ap_success, ap_msg = self.enable_ap_mode(force=True)
                     if ap_success:
                         logger.info("AP mode enabled as failsafe")
                         return False, "Connection failed. AP mode enabled."
@@ -1400,7 +1426,7 @@ class WiFiManager:
                     logger.error(f"Failed to restore after exception: {restore_error}")
                     # Last resort: enable AP mode
                     try:
-                        self.enable_ap_mode()
+                        self.enable_ap_mode(force=True)
                     except Exception as ap_error:  # nosec B110 - last-resort; do not re-raise, but log for debugging
                         logger.error("Last-resort AP mode enable failed in recovery path: %s", ap_error, exc_info=True)
             return False, str(e)
@@ -1464,26 +1490,29 @@ class WiFiManager:
             # Show LED message
             self._show_led_message(f"Connecting to {ssid}...", duration=10)
             
-            # First, check if connection already exists and try to activate it
-            # NetworkManager connection names might not match SSID exactly, so search by SSID
-            check_result = subprocess.run(
-                ["nmcli", "-t", "-f", "NAME,802-11-wireless.ssid", "connection", "show"],
-                capture_output=True,
-                text=True,
-                timeout=5
+            # Find existing NM connection for this SSID.
+            # 802-11-wireless.ssid is not a valid column in 'nmcli connection show',
+            # so list all wifi connections then query each one's SSID individually.
+            list_result = subprocess.run(  # nosec B603 B607 - fixed args, no user input
+                ["nmcli", "-t", "-f", "NAME,TYPE", "connection", "show"],
+                capture_output=True, text=True, timeout=5
             )
-            
             existing_conn_name = None
-            if check_result.returncode == 0:
-                for line in check_result.stdout.strip().split('\n'):
-                    if ':' in line:
-                        parts = line.split(':')
-                        if len(parts) >= 2:
-                            conn_name = parts[0].strip()
-                            conn_ssid = parts[1].strip() if len(parts) > 1 else ""
-                            if conn_ssid == ssid:
-                                existing_conn_name = conn_name
-                                break
+            if list_result.returncode == 0:
+                for line in list_result.stdout.strip().split('\n'):
+                    if ':' not in line:
+                        continue
+                    parts = line.split(':')
+                    if len(parts) < 2 or parts[1].strip() != '802-11-wireless':
+                        continue
+                    conn_name = parts[0].strip()
+                    ssid_r = subprocess.run(  # nosec B603 B607 - conn_name from nmcli output, not user input
+                        ["nmcli", "-g", "802-11-wireless.ssid", "connection", "show", conn_name],
+                        capture_output=True, text=True, timeout=5
+                    )
+                    if ssid_r.returncode == 0 and ssid_r.stdout.strip() == ssid:
+                        existing_conn_name = conn_name
+                        break
             
             # Also try direct lookup by SSID (in case connection name matches SSID)
             if not existing_conn_name:
@@ -1855,7 +1884,7 @@ class WiFiManager:
         logger.warning(f"Failed to enable WiFi radio after {max_retries} attempts")
         return False
     
-    def enable_ap_mode(self) -> Tuple[bool, str]:
+    def enable_ap_mode(self, force: bool = False) -> Tuple[bool, str]:
         """
         Enable access point mode
         
@@ -1877,20 +1906,29 @@ class WiFiManager:
             if not self._ensure_wifi_radio_enabled():
                 return False, "WiFi radio is disabled and could not be enabled"
             
-            # Check if WiFi is connected
+            # Check if WiFi is connected (skip when force=True)
             status = self.get_wifi_status()
-            if status.connected:
+            if not force and status.connected:
                 return False, "Cannot enable AP mode while WiFi is connected"
             
-            # Check if Ethernet is connected
-            if self._is_ethernet_connected():
+            # Check if Ethernet is connected (skip when force=True)
+            if not force and self._is_ethernet_connected():
                 return False, "Cannot enable AP mode while Ethernet is connected"
             
+            if force:
+                logger.debug(f"enable_ap_mode: force=True — WiFi/Ethernet guards bypassed; will create {self._FORCE_AP_FLAG_PATH}")
+
             # Try hostapd/dnsmasq first (captive portal mode)
             if self.has_hostapd and self.has_dnsmasq:
                 result = self._enable_ap_mode_hostapd()
                 if result[0]:
                     self._ap_enabled_at = time.time()
+                    if force:
+                        try:
+                            self._FORCE_AP_FLAG_PATH.touch()
+                            logger.debug(f"Force-AP flag created: {self._FORCE_AP_FLAG_PATH}")
+                        except OSError as exc:
+                            logger.warning(f"Failed to create force-AP flag {self._FORCE_AP_FLAG_PATH}: {exc}")
                     return result
 
             # Fallback to nmcli hotspot (simpler, no captive portal)
@@ -1900,6 +1938,12 @@ class WiFiManager:
                 result = self._enable_ap_mode_nmcli_hotspot()
                 if result[0]:
                     self._ap_enabled_at = time.time()
+                    if force:
+                        try:
+                            self._FORCE_AP_FLAG_PATH.touch()
+                            logger.debug(f"Force-AP flag created: {self._FORCE_AP_FLAG_PATH}")
+                        except OSError as exc:
+                            logger.warning(f"Failed to create force-AP flag {self._FORCE_AP_FLAG_PATH}: {exc}")
                 return result
 
             return False, "No WiFi tools available (nmcli, hostapd, or dnsmasq required)"
@@ -2091,8 +2135,14 @@ class WiFiManager:
                 self._clear_led_message()
                 return False, "AP started but captive-portal redirect setup failed"
 
-            # Verify the AP is actually running
-            status = self._get_ap_status_nmcli()
+            # Verify the AP is actually running (retry up to 5x with 2s delay for NM async activation)
+            status = {}
+            for _attempt in range(5):
+                status = self._get_ap_status_nmcli()
+                if status.get('active'):
+                    break
+                logger.debug(f"AP verification attempt {_attempt + 1}/5 not yet active, waiting 2s")
+                time.sleep(2)
             if status.get('active'):
                 ip = status.get('ip', '192.168.4.1')
                 logger.info(f"AP mode confirmed active at {ip} (open network, no password)")
@@ -2290,6 +2340,7 @@ class WiFiManager:
                         logger.warning("WiFi radio may be disabled after nmcli AP cleanup")
 
                 self._ap_enabled_at = None
+                self._FORCE_AP_FLAG_PATH.unlink(missing_ok=True)
                 logger.info("AP mode disabled successfully")
                 return True, "AP mode disabled"
             except Exception as e:
@@ -2478,22 +2529,29 @@ address=/detectportal.firefox.com/192.168.4.1
                 else:
                     logger.warning(f"Failed to enable AP mode: {message}")
             elif not should_have_ap and ap_active:
-                # Should not have AP but do - disable AP mode
-                # Always disable if WiFi or Ethernet connects, regardless of auto_enable setting
-                if status.connected or ethernet_connected:
+                # Should not have AP but do - check if it was manually force-enabled
+                force_active = self._FORCE_AP_FLAG_PATH.exists()
+                if status.connected:
+                    # WiFi connected: always disable AP (user successfully configured WiFi)
                     success, message = self.disable_ap_mode()
                     if success:
-                        if status.connected:
-                            logger.info("Auto-disabled AP mode (WiFi connected)")
-                        elif ethernet_connected:
-                            logger.info("Auto-disabled AP mode (Ethernet connected)")
-                        self._disconnected_checks = 0  # Reset counter
+                        logger.info("Auto-disabled AP mode (WiFi connected)")
+                        self._disconnected_checks = 0
                         return True
                     else:
                         logger.warning(f"Failed to auto-disable AP mode: {message}")
+                elif ethernet_connected and not force_active:
+                    # Ethernet connected, AP not manually forced: auto-disable
+                    success, message = self.disable_ap_mode()
+                    if success:
+                        logger.info("Auto-disabled AP mode (Ethernet connected)")
+                        self._disconnected_checks = 0
+                        return True
+                    else:
+                        logger.warning(f"Failed to auto-disable AP mode: {message}")
+                elif ethernet_connected and force_active:
+                    logger.debug("AP mode is force-active; Ethernet connected but auto-disable suppressed")
                 elif not auto_enable:
-                    # AP is active but auto_enable is disabled - this means it was manually enabled
-                    # Don't disable it automatically, let it stay active
                     logger.debug("AP mode is active (manually enabled), keeping active")
 
             # Idle-timeout check: disable AP if no client has connected within the window.

web_interface/app.py

@@ -2,8 +2,10 @@ from flask import Flask, request, redirect, url_for, jsonify, Response, send_fro
 import json
 import logging
 import os
+import queue
 import sys
 import subprocess
+import threading
 import time
 from pathlib import Path
 from datetime import datetime, timedelta
@@ -413,13 +415,53 @@ def add_security_headers(response):
     
     return response
 
-# SSE helper function
-def sse_response(generator_func):
-    """Helper to create SSE responses"""
-    def generate():
-        for data in generator_func():
-            yield f"data: {json.dumps(data)}\n\n"
-    return Response(generate(), mimetype='text/event-stream')
+class _StreamBroadcaster:
+    """Fan-out broadcaster: one background generator thread pushes to all SSE clients.
+
+    This means N browser tabs share one generator instead of each running their own,
+    keeping PIL encodes / subprocess forks constant regardless of how many tabs are open.
+    """
+
+    def __init__(self, generator_factory):
+        self._generator_factory = generator_factory
+        self._clients: set = set()
+        self._lock = threading.Lock()
+        self._thread: threading.Thread | None = None
+
+    def subscribe(self) -> queue.Queue:
+        q: queue.Queue = queue.Queue(maxsize=5)
+        with self._lock:
+            self._clients.add(q)
+            if not (self._thread and self._thread.is_alive()):
+                self._thread = threading.Thread(target=self._broadcast, daemon=True)
+                self._thread.start()
+        return q
+
+    def unsubscribe(self, q: queue.Queue) -> None:
+        with self._lock:
+            self._clients.discard(q)
+
+    def _broadcast(self):
+        for data in self._generator_factory():
+            with self._lock:
+                if not self._clients:
+                    # No subscribers — exit so the thread doesn't spin indefinitely.
+                    # subscribe() will restart it when a new client arrives.
+                    break
+                for q in self._clients:
+                    try:
+                        q.put_nowait(data)
+                    except queue.Full:
+                        # Client is reading too slowly; drop the oldest item and
+                        # deliver the latest so the queue never stalls the client.
+                        try:
+                            q.get_nowait()
+                        except queue.Empty:
+                            pass
+                        try:
+                            q.put_nowait(data)
+                        except queue.Full:
+                            pass
 
 # System status generator for SSE
 def system_status_generator():
@@ -596,20 +638,50 @@ def logs_generator():
 
         time.sleep(5)  # Update every 5 seconds (reduced frequency for better performance)
 
+# One broadcaster per stream — shared across all SSE clients
+_stats_broadcaster = _StreamBroadcaster(system_status_generator)
+_display_broadcaster = _StreamBroadcaster(display_preview_generator)
+_logs_broadcaster = _StreamBroadcaster(logs_generator)
+
+
+def _sse_stream(broadcaster: _StreamBroadcaster) -> Response:
+    """Return a streaming SSE response backed by a shared broadcaster."""
+    q = broadcaster.subscribe()
+
+    def generate():
+        try:
+            while True:
+                try:
+                    data = q.get(timeout=30)
+                    yield f"data: {json.dumps(data)}\n\n"
+                except queue.Empty:
+                    # Send an SSE comment heartbeat to keep the connection alive
+                    # through proxies that close idle connections.
+                    yield ": heartbeat\n\n"
+        except GeneratorExit:
+            pass
+        finally:
+            broadcaster.unsubscribe(q)
+
+    return Response(generate(), mimetype='text/event-stream')
+
+
 # SSE endpoints
 @app.route('/api/v3/stream/stats')
 def stream_stats():
-    return sse_response(system_status_generator)
+    return _sse_stream(_stats_broadcaster)
 
 @app.route('/api/v3/stream/display')
 def stream_display():
-    return sse_response(display_preview_generator)
+    return _sse_stream(_display_broadcaster)
 
 @app.route('/api/v3/stream/logs')
 def stream_logs():
-    return sse_response(logs_generator)
+    return _sse_stream(_logs_broadcaster)
 
-# Exempt SSE streams from CSRF and add rate limiting
+# Exempt SSE streams from CSRF and apply a generous rate limit.
+# SSE connections are long-lived HTTP requests, not repeated API calls, so the
+# tight "20 per minute" default would be exhausted quickly on reconnects.
 if csrf:
     csrf.exempt(stream_stats)
     csrf.exempt(stream_display)
@@ -617,9 +689,9 @@ if csrf:
     # Note: api_v3 blueprint is exempted above after registration
 
 if limiter:
-    limiter.limit("20 per minute")(stream_stats)
-    limiter.limit("20 per minute")(stream_display)
-    limiter.limit("20 per minute")(stream_logs)
+    limiter.limit("200 per minute")(stream_stats)
+    limiter.limit("200 per minute")(stream_display)
+    limiter.limit("200 per minute")(stream_logs)
 
 # Main route - redirect to v3 interface as default
 @app.route('/')

web_interface/blueprints/api_v3.py

@@ -6542,7 +6542,7 @@ def scan_wifi_networks():
         ap_was_active = wifi_manager._is_ap_mode_active()
 
         # Perform the scan (this will handle AP mode disabling/enabling internally)
-        networks = wifi_manager.scan_networks()
+        networks, _was_cached = wifi_manager.scan_networks()
 
         # Convert to dict format
         networks_data = [
@@ -6680,7 +6680,9 @@ def enable_ap_mode():
         from src.wifi_manager import WiFiManager
 
         wifi_manager = WiFiManager()
-        success, message = wifi_manager.enable_ap_mode()
+        _force_raw = (request.get_json(silent=True) or {}).get('force', False)
+        force = _force_raw is True or (isinstance(_force_raw, str) and _force_raw.lower() in ('true', '1'))
+        success, message = wifi_manager.enable_ap_mode(force=force)
 
         if success:
             return jsonify({

web_interface/static/v3/app.js

@@ -1,4 +1,4 @@
-/* global showNotification, updateSystemStats, htmx */
+/* global showNotification, updateSystemStats, updateDisplayPreview, htmx */
 // LED Matrix v3 JavaScript
 // Additional helpers for HTMX and Alpine.js integration
 
@@ -51,7 +51,8 @@ document.body.addEventListener('htmx:afterRequest', function(event) {
     }
 });
 
-// SSE reconnection helper
+// SSE reconnection helper — closes and reopens both SSE streams,
+// reattaching the open/error handlers defined in base.html.
 window.reconnectSSE = function() {
     if (window.statsSource) {
         window.statsSource.close();
@@ -60,14 +61,18 @@ window.reconnectSSE = function() {
             const data = JSON.parse(event.data);
             if (typeof updateSystemStats === 'function') updateSystemStats(data);
         };
+        if (window._statsOpenHandler) window.statsSource.addEventListener('open', window._statsOpenHandler);
+        if (window._statsErrorHandler) window.statsSource.addEventListener('error', window._statsErrorHandler);
     }
 
     if (window.displaySource) {
         window.displaySource.close();
         window.displaySource = new EventSource('/api/v3/stream/display');
-        window.displaySource.onmessage = function() {
-            // Handle display updates
+        window.displaySource.onmessage = function(event) {
+            const data = JSON.parse(event.data);
+            if (typeof updateDisplayPreview === 'function') updateDisplayPreview(data);
         };
+        if (window._displayErrorHandler) window.displaySource.addEventListener('error', window._displayErrorHandler);
     }
 };
 

web_interface/static/v3/js/widgets/json-file-manager.js

@@ -0,0 +1,782 @@
+/**
+ * JsonFileManager — reusable JSON file management widget for LEDMatrix plugins.
+ *
+ * Usage via config_schema.json:
+ *   "file_manager": {
+ *     "type": "null",
+ *     "title": "Data Files",
+ *     "x-widget": "json-file-manager",
+ *     "x-widget-config": {
+ *       "actions": {
+ *         "list":   "list-files",   // required
+ *         "get":    "get-file",     // required for editing
+ *         "save":   "save-file",    // required for editing
+ *         "upload": "upload-file",  // optional
+ *         "delete": "delete-file",  // optional
+ *         "create": "create-file",  // optional
+ *         "toggle": "toggle-category" // optional
+ *       },
+ *       "upload_hint":      "Hint text under the drop zone",
+ *       "directory_label":  "of_the_day/",
+ *       "create_fields": [
+ *         { "key": "category_name", "label": "Category Name",
+ *           "placeholder": "my_words", "pattern": "^[a-z0-9_]+$",
+ *           "hint": "Used as filename" },
+ *         { "key": "display_name", "label": "Display Name",
+ *           "placeholder": "My Words" }
+ *       ],
+ *       "toggle_key": "category_name"
+ *     }
+ *   }
+ *
+ * No CDN dependencies. Works on all modern browsers.
+ */
+(function () {
+    'use strict';
+
+    class JsonFileManager {
+        constructor(container, config, pluginId) {
+            // Prevent duplicate instances on the same container
+            if (container._jfmInstance) {
+                container._jfmInstance._destroy();
+            }
+            container._jfmInstance = this;
+
+            this.el         = container;
+            this.pluginId   = pluginId;
+            this.actions    = config.actions || {};
+            this.uploadHint = config.upload_hint || '';
+            this.dirLabel   = config.directory_label || '';
+            this.createFields = config.create_fields || [];
+            this.toggleKey  = config.toggle_key || null;
+
+            // Unique prefix for all DOM IDs in this instance
+            this._uid = 'jfm_' + Math.random().toString(36).slice(2, 9);
+
+            // Mutable state
+            this._editFile   = null;
+            this._deleteFile = null;
+            this._keyHandler = this._onKey.bind(this);
+
+            this._inject();
+            this._bind();
+            this._loadList();
+        }
+
+        // ── Lifecycle ────────────────────────────────────────────────────────
+
+        _destroy() {
+            document.removeEventListener('keydown', this._keyHandler);
+            this.el._jfmInstance = null;
+        }
+
+        // ── DOM Injection ────────────────────────────────────────────────────
+
+        _inject() {
+            const u = this._uid;
+            const hasUpload = !!this.actions.upload;
+            const hasCreate = !!this.actions.create;
+            const hasDelete = !!this.actions.delete;
+
+            this.el.innerHTML = this._css(u) + `
+<div id="${u}" class="jfm">
+
+  <div class="jfm-header">
+    <div class="jfm-header-left">
+      <span class="jfm-title">Data Files</span>
+      ${this.dirLabel ? `<code class="jfm-dir">${this._esc(this.dirLabel)}</code>` : ''}
+    </div>
+    <div class="jfm-header-right">
+      ${hasCreate ? `<button class="jfm-btn jfm-btn-primary jfm-btn-sm" data-jfm="open-create">+ New File</button>` : ''}
+      <button class="jfm-btn jfm-btn-ghost jfm-btn-sm" data-jfm="refresh" title="Refresh file list">&#8635;</button>
+    </div>
+  </div>
+
+  <div id="${u}-list" class="jfm-list">
+    <div class="jfm-loading"><span class="jfm-spin"></span> Loading…</div>
+  </div>
+
+  ${hasUpload ? `
+  <div class="jfm-upload-wrap">
+    <input type="file" accept=".json" id="${u}-fileinput" tabindex="-1">
+    <div class="jfm-dropzone" id="${u}-dropzone" data-jfm="open-picker" role="button" tabindex="0"
+         aria-label="Upload JSON file">
+      <span class="jfm-drop-icon">&#128193;</span>
+      <p class="jfm-drop-primary">Drop a JSON file here, or click to browse</p>
+      ${this.uploadHint ? `<p class="jfm-drop-hint">${this._esc(this.uploadHint)}</p>` : ''}
+    </div>
+  </div>` : ''}
+
+  <!-- ── Edit modal ─────────────────────────────────────── -->
+  <div class="jfm-modal" id="${u}-edit-modal" role="dialog" aria-modal="true" hidden>
+    <div class="jfm-modal-box jfm-modal-wide">
+      <div class="jfm-modal-head">
+        <span id="${u}-edit-title" class="jfm-modal-title">Edit file</span>
+        <div class="jfm-modal-tools">
+          <button class="jfm-btn jfm-btn-ghost jfm-btn-sm" data-jfm="fmt">Format</button>
+          <button class="jfm-btn jfm-btn-ghost jfm-btn-sm" data-jfm="validate">Validate</button>
+          <button class="jfm-close-btn" data-jfm="close-edit" aria-label="Close">&times;</button>
+        </div>
+      </div>
+      <div id="${u}-edit-err" class="jfm-err-bar" hidden></div>
+      <textarea id="${u}-editor" class="jfm-editor"
+                spellcheck="false" autocomplete="off"
+                autocorrect="off" autocapitalize="off"
+                aria-label="JSON editor"></textarea>
+      <div class="jfm-modal-foot">
+        <span id="${u}-charcount" class="jfm-stat"></span>
+        <button class="jfm-btn jfm-btn-ghost" data-jfm="close-edit">Cancel</button>
+        <button class="jfm-btn jfm-btn-primary" data-jfm="save" id="${u}-save-btn">Save</button>
+      </div>
+    </div>
+  </div>
+
+  <!-- ── Delete modal ───────────────────────────────────── -->
+  ${hasDelete ? `
+  <div class="jfm-modal" id="${u}-del-modal" role="dialog" aria-modal="true" hidden>
+    <div class="jfm-modal-box">
+      <div class="jfm-modal-head">
+        <span class="jfm-modal-title">Delete file</span>
+        <button class="jfm-close-btn" data-jfm="close-del" aria-label="Close">&times;</button>
+      </div>
+      <div class="jfm-modal-body">
+        <p>Delete <strong id="${u}-del-name"></strong>?</p>
+        <p class="jfm-muted">This permanently removes the file and its entry from the plugin configuration.</p>
+      </div>
+      <div class="jfm-modal-foot">
+        <button class="jfm-btn jfm-btn-ghost" data-jfm="close-del">Cancel</button>
+        <button class="jfm-btn jfm-btn-danger" data-jfm="confirm-del" id="${u}-del-btn">Delete</button>
+      </div>
+    </div>
+  </div>` : ''}
+
+  <!-- ── Create modal ───────────────────────────────────── -->
+  ${hasCreate ? `
+  <div class="jfm-modal" id="${u}-create-modal" role="dialog" aria-modal="true" hidden>
+    <div class="jfm-modal-box">
+      <div class="jfm-modal-head">
+        <span class="jfm-modal-title">Create new file</span>
+        <button class="jfm-close-btn" data-jfm="close-create" aria-label="Close">&times;</button>
+      </div>
+      <div class="jfm-modal-body">
+        ${this.createFields.map(f => `
+        <div class="jfm-field">
+          <label for="${u}-cf-${this._esc(f.key)}">${this._esc(f.label)}</label>
+          <input type="text" id="${u}-cf-${this._esc(f.key)}"
+                 placeholder="${this._esc(f.placeholder || '')}"
+                 ${f.pattern ? `pattern="${this._esc(f.pattern)}"` : ''}>
+          ${f.hint ? `<span class="jfm-hint">${this._esc(f.hint)}</span>` : ''}
+        </div>`).join('')}
+      </div>
+      <div class="jfm-modal-foot">
+        <button class="jfm-btn jfm-btn-ghost" data-jfm="close-create">Cancel</button>
+        <button class="jfm-btn jfm-btn-primary" data-jfm="do-create" id="${u}-create-btn">Create</button>
+      </div>
+    </div>
+  </div>` : ''}
+
+</div>`;  // end #${u}
+
+            // Cache frequently-used elements
+            this._root        = document.getElementById(u);
+            this._listEl      = document.getElementById(`${u}-list`);
+            this._editorEl    = document.getElementById(`${u}-editor`);
+            this._editModal   = document.getElementById(`${u}-edit-modal`);
+            this._delModal    = document.getElementById(`${u}-del-modal`);
+            this._createModal = document.getElementById(`${u}-create-modal`);
+            this._dropzone    = document.getElementById(`${u}-dropzone`);
+            this._fileInput   = document.getElementById(`${u}-fileinput`);
+        }
+
+        _css(u) {
+            return `<style>
+#${u}{font-family:inherit;color:#111827;}
+#${u} *{box-sizing:border-box;}
+
+/* Header */
+#${u} .jfm-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:.875rem;gap:.5rem;}
+#${u} .jfm-header-left{display:flex;align-items:center;gap:.5rem;flex-wrap:wrap;}
+#${u} .jfm-title{font-size:.9375rem;font-weight:600;color:#111827;}
+#${u} .jfm-dir{font-size:.75rem;color:#6b7280;background:#f3f4f6;padding:.125rem .375rem;border-radius:.25rem;font-family:monospace;}
+#${u} .jfm-header-right{display:flex;gap:.375rem;align-items:center;flex-shrink:0;}
+
+/* Buttons */
+#${u} .jfm-btn{display:inline-flex;align-items:center;gap:.25rem;padding:.4375rem .875rem;border-radius:.375rem;border:1px solid #d1d5db;background:#fff;color:#374151;font-size:.875rem;font-weight:500;cursor:pointer;transition:background .12s,border-color .12s,opacity .12s;line-height:1.25;}
+#${u} .jfm-btn:hover:not(:disabled){background:#f9fafb;border-color:#9ca3af;}
+#${u} .jfm-btn:focus-visible{outline:2px solid #3b82f6;outline-offset:1px;}
+#${u} .jfm-btn:disabled{opacity:.5;cursor:not-allowed;}
+#${u} .jfm-btn-sm{padding:.3125rem .625rem;font-size:.8125rem;}
+#${u} .jfm-btn-primary{background:#3b82f6;border-color:#3b82f6;color:#fff;}
+#${u} .jfm-btn-primary:hover:not(:disabled){background:#2563eb;border-color:#2563eb;}
+#${u} .jfm-btn-danger{background:#ef4444;border-color:#ef4444;color:#fff;}
+#${u} .jfm-btn-danger:hover:not(:disabled){background:#dc2626;border-color:#dc2626;}
+#${u} .jfm-btn-ghost{background:transparent;border-color:transparent;color:#6b7280;}
+#${u} .jfm-btn-ghost:hover:not(:disabled){background:#f3f4f6;color:#374151;}
+#${u} .jfm-close-btn{display:flex;align-items:center;justify-content:center;width:2rem;height:2rem;border:none;background:none;color:#9ca3af;font-size:1.25rem;cursor:pointer;border-radius:.25rem;padding:0;line-height:1;}
+#${u} .jfm-close-btn:hover{background:#f3f4f6;color:#374151;}
+
+/* File list */
+#${u} .jfm-list{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:.625rem;margin-bottom:1rem;min-height:5rem;}
+#${u} .jfm-loading{grid-column:1/-1;display:flex;align-items:center;justify-content:center;gap:.5rem;padding:2rem;color:#6b7280;font-size:.875rem;}
+#${u} .jfm-empty{grid-column:1/-1;text-align:center;padding:2.5rem 1rem;color:#9ca3af;}
+#${u} .jfm-empty-icon{font-size:2.25rem;margin-bottom:.625rem;}
+#${u} .jfm-empty-title{font-weight:600;color:#374151;margin:0 0 .25rem;}
+#${u} .jfm-empty-sub{font-size:.875rem;margin:0;}
+
+/* File cards */
+#${u} .jfm-card{border:1px solid #e5e7eb;border-radius:.5rem;padding:.875rem;background:#fff;display:flex;flex-direction:column;gap:.5rem;transition:border-color .15s,box-shadow .15s;}
+#${u} .jfm-card:hover{border-color:#93c5fd;box-shadow:0 2px 8px rgba(59,130,246,.1);}
+#${u} .jfm-card.jfm-off{opacity:.6;}
+#${u} .jfm-card-top{display:flex;justify-content:space-between;align-items:flex-start;gap:.5rem;}
+#${u} .jfm-card-name{font-weight:600;font-size:.9375rem;word-break:break-word;color:#111827;flex:1;}
+#${u} .jfm-card-meta{font-size:.75rem;color:#6b7280;display:flex;flex-direction:column;gap:.125rem;line-height:1.5;}
+#${u} .jfm-card-actions{display:flex;gap:.375rem;padding-top:.5rem;border-top:1px solid #f3f4f6;margin-top:.125rem;}
+#${u} .jfm-card-actions .jfm-btn{flex:1;justify-content:center;}
+#${u} .jfm-card-actions .jfm-del{flex:0 0 auto;}
+
+/* Toggle */
+#${u} .jfm-toggle{display:flex;align-items:center;gap:.3125rem;font-size:.75rem;color:#6b7280;white-space:nowrap;flex-shrink:0;}
+#${u} .jfm-toggle input[type=checkbox]{width:.9375rem;height:.9375rem;cursor:pointer;accent-color:#22c55e;margin:0;}
+
+/* Upload zone */
+#${u} .jfm-upload-wrap{margin-top:.25rem;}
+#${u} input[type=file]#${u}-fileinput{position:absolute;left:-9999px;width:1px;height:1px;opacity:0;}
+#${u} .jfm-dropzone{border:2px dashed #d1d5db;border-radius:.5rem;padding:1.25rem 1rem;text-align:center;cursor:pointer;transition:border-color .15s,background .15s;background:#f9fafb;user-select:none;}
+#${u} .jfm-dropzone:hover,#${u} .jfm-dropzone:focus-visible,#${u} .jfm-dropzone.jfm-over{border-color:#3b82f6;background:#eff6ff;border-style:solid;outline:none;}
+#${u} .jfm-drop-icon{font-size:1.75rem;display:block;margin-bottom:.375rem;}
+#${u} .jfm-drop-primary{font-size:.875rem;color:#374151;margin:0 0 .25rem;}
+#${u} .jfm-drop-hint{font-size:.75rem;color:#9ca3af;margin:0;}
+
+/* Modals */
+#${u} .jfm-modal{position:fixed;inset:0;background:rgba(0,0,0,.45);z-index:9999;display:flex;align-items:center;justify-content:center;padding:1rem;backdrop-filter:blur(1px);}
+#${u} .jfm-modal[hidden]{display:none;}
+#${u} .jfm-modal-box{background:#fff;border-radius:.5rem;box-shadow:0 20px 40px rgba(0,0,0,.15);display:flex;flex-direction:column;width:100%;max-width:440px;max-height:92vh;}
+#${u} .jfm-modal-wide{max-width:880px;}
+#${u} .jfm-modal-head{display:flex;justify-content:space-between;align-items:center;padding:.875rem 1.125rem;border-bottom:1px solid #e5e7eb;flex-shrink:0;gap:.5rem;}
+#${u} .jfm-modal-title{font-weight:600;font-size:.9375rem;color:#111827;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
+#${u} .jfm-modal-tools{display:flex;gap:.25rem;align-items:center;flex-shrink:0;}
+#${u} .jfm-modal-body{padding:1.125rem;overflow-y:auto;flex:1;}
+#${u} .jfm-modal-foot{display:flex;gap:.5rem;justify-content:flex-end;align-items:center;padding:.75rem 1.125rem;border-top:1px solid #e5e7eb;flex-shrink:0;background:#f9fafb;border-radius:0 0 .5rem .5rem;}
+#${u} .jfm-stat{margin-right:auto;font-size:.75rem;color:#9ca3af;font-variant-numeric:tabular-nums;}
+
+/* JSON editor */
+#${u} .jfm-editor{display:block;width:100%;min-height:400px;height:58vh;max-height:64vh;resize:vertical;font-family:'Courier New',Consolas,ui-monospace,monospace;font-size:.8rem;line-height:1.55;padding:.75rem 1rem;border:none;border-radius:0;outline:none;white-space:pre;overflow:auto;color:#1e293b;background:#fafafa;tab-size:2;}
+#${u} .jfm-err-bar{background:#fef2f2;border-bottom:1px solid #fecaca;color:#991b1b;font-size:.8125rem;padding:.5rem 1.125rem;flex-shrink:0;line-height:1.4;}
+#${u} .jfm-err-bar[hidden]{display:none;}
+
+/* Create form */
+#${u} .jfm-field{margin-bottom:.875rem;}
+#${u} .jfm-field:last-child{margin-bottom:0;}
+#${u} .jfm-field label{display:block;font-size:.875rem;font-weight:500;color:#374151;margin-bottom:.3125rem;}
+#${u} .jfm-field input{width:100%;padding:.4375rem .75rem;border:1px solid #d1d5db;border-radius:.375rem;font-size:.875rem;color:#111827;background:#fff;}
+#${u} .jfm-field input:focus{outline:none;border-color:#3b82f6;box-shadow:0 0 0 3px rgba(59,130,246,.12);}
+#${u} .jfm-hint{display:block;font-size:.75rem;color:#9ca3af;margin-top:.25rem;}
+#${u} .jfm-muted{font-size:.875rem;color:#6b7280;margin-top:.375rem;}
+
+/* Spinner */
+#${u} .jfm-spin{display:inline-block;width:.9rem;height:.9rem;border:2px solid #e5e7eb;border-top-color:#3b82f6;border-radius:50%;animation:jfm-spin-${u} .6s linear infinite;vertical-align:middle;}
+@keyframes jfm-spin-${u}{to{transform:rotate(360deg);}}
+</style>`;
+        }
+
+        // ── Event Binding ────────────────────────────────────────────────────
+
+        _bind() {
+            // Delegated clicks on the widget root
+            this._root.addEventListener('click', this._onClick.bind(this));
+            this._root.addEventListener('change', this._onChange.bind(this));
+
+            // Drag-and-drop on the dropzone
+            if (this._dropzone) {
+                this._dropzone.addEventListener('dragover', e => {
+                    e.preventDefault();
+                    this._dropzone.classList.add('jfm-over');
+                });
+                this._dropzone.addEventListener('dragleave', () => {
+                    this._dropzone.classList.remove('jfm-over');
+                });
+                this._dropzone.addEventListener('drop', e => {
+                    e.preventDefault();
+                    this._dropzone.classList.remove('jfm-over');
+                    const file = e.dataTransfer?.files[0];
+                    if (file) this._uploadFile(file);
+                });
+                // Keyboard activation of drop zone
+                this._dropzone.addEventListener('keydown', e => {
+                    if (e.key === 'Enter' || e.key === ' ') {
+                        e.preventDefault();
+                        this._fileInput?.click();
+                    }
+                });
+            }
+
+            // Modal backdrop clicks
+            [this._editModal, this._delModal, this._createModal].forEach(m => {
+                if (m) m.addEventListener('click', e => { if (e.target === m) this._closeAll(); });
+            });
+
+            // Editor: char count + Tab indent
+            if (this._editorEl) {
+                this._editorEl.addEventListener('input', () => this._updateStat());
+                this._editorEl.addEventListener('keydown', e => {
+                    if (e.key === 'Tab') {
+                        e.preventDefault();
+                        const s = this._editorEl.selectionStart;
+                        const end = this._editorEl.selectionEnd;
+                        const v = this._editorEl.value;
+                        this._editorEl.value = v.slice(0, s) + '  ' + v.slice(end);
+                        this._editorEl.selectionStart = this._editorEl.selectionEnd = s + 2;
+                        this._updateStat();
+                    }
+                });
+            }
+
+            // Global keyboard shortcuts
+            document.addEventListener('keydown', this._keyHandler);
+        }
+
+        _onKey(e) {
+            const editOpen   = this._editModal   && !this._editModal.hidden;
+            const delOpen    = this._delModal    && !this._delModal.hidden;
+            const createOpen = this._createModal && !this._createModal.hidden;
+
+            if (e.key === 'Escape') {
+                if (editOpen)   { this._closeEdit();   return; }
+                if (delOpen)    { this._closeDel();    return; }
+                if (createOpen) { this._closeCreate(); return; }
+            }
+            if ((e.ctrlKey || e.metaKey) && e.key === 's' && editOpen) {
+                e.preventDefault();
+                this._doSave();
+            }
+        }
+
+        _onClick(e) {
+            const btn = e.target.closest('[data-jfm]');
+            if (!btn) return;
+            const action = btn.dataset.jfm;
+
+            switch (action) {
+                case 'refresh':      this._loadList(); break;
+                case 'open-picker':  this._fileInput?.click(); break;
+                case 'open-create':  this._openCreate(); break;
+                case 'close-edit':   this._closeEdit(); break;
+                case 'close-del':    this._closeDel(); break;
+                case 'close-create': this._closeCreate(); break;
+                case 'fmt':          this._formatJson(); break;
+                case 'validate':     this._validateJson(); break;
+                case 'save':         this._doSave(); break;
+                case 'confirm-del':  this._doDelete(); break;
+                case 'do-create':    this._doCreate(); break;
+                case 'edit-file': {
+                    const card = btn.closest('[data-jfm-file]');
+                    if (card) this._openEdit(card.dataset.jfmFile);
+                    break;
+                }
+                case 'del-file': {
+                    const card = btn.closest('[data-jfm-file]');
+                    if (card) this._openDel(card.dataset.jfmFile);
+                    break;
+                }
+            }
+        }
+
+        _onChange(e) {
+            // Toggle checkbox
+            if (e.target.classList.contains('jfm-toggle-cb')) {
+                const catName = e.target.dataset.cat;
+                const enabled = e.target.checked;
+                this._doToggle(catName, enabled, e.target);
+            }
+            // File input
+            if (e.target === this._fileInput) {
+                const file = e.target.files?.[0];
+                if (file) this._uploadFile(file);
+                e.target.value = '';
+            }
+        }
+
+        // ── API helper ───────────────────────────────────────────────────────
+
+        async _api(actionKey, params) {
+            const actionId = this.actions[actionKey];
+            if (!actionId) throw new Error(`Action "${actionKey}" not configured`);
+            const body = { plugin_id: this.pluginId, action_id: actionId };
+            if (params !== undefined) body.params = params;
+            const r = await fetch('/api/v3/plugins/action', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify(body)
+            });
+            if (!r.ok) throw new Error('Server error ' + r.status);
+            const ct = r.headers.get('content-type') || '';
+            if (!ct.includes('application/json')) {
+                const txt = await r.text();
+                throw new Error('Unexpected response: ' + txt.slice(0, 120));
+            }
+            return r.json();
+        }
+
+        // ── File List ────────────────────────────────────────────────────────
+
+        async _loadList() {
+            this._listEl.innerHTML = `<div class="jfm-loading"><span class="jfm-spin"></span> Loading…</div>`;
+            try {
+                const data = await this._api('list');
+                if (data.status !== 'success') throw new Error(data.message || 'Load failed');
+                this._renderList(data.files || []);
+            } catch (err) {
+                this._listEl.innerHTML = `
+                    <div class="jfm-empty">
+                        <div class="jfm-empty-icon">&#9888;</div>
+                        <p class="jfm-empty-title">Failed to load files</p>
+                        <p class="jfm-empty-sub">${this._esc(err.message)}</p>
+                    </div>`;
+            }
+        }
+
+        _renderList(files) {
+            if (!files.length) {
+                this._listEl.innerHTML = `
+                    <div class="jfm-empty">
+                        <div class="jfm-empty-icon">&#128193;</div>
+                        <p class="jfm-empty-title">No files yet</p>
+                        <p class="jfm-empty-sub">Upload or create a JSON file to get started</p>
+                    </div>`;
+                return;
+            }
+            this._listEl.innerHTML = files.map(f => this._card(f)).join('');
+        }
+
+        _card(f) {
+            const u           = this._uid;
+            const enabled     = f.enabled !== false;
+            const displayName = this._esc(f.display_name || f.filename);
+            const filename    = this._esc(f.filename);
+            const catName     = this.toggleKey ? this._esc(f[this.toggleKey] || '') : '';
+            const showToggle  = !!(this.actions.toggle && this.toggleKey && f[this.toggleKey]);
+            const hasEdit     = !!this.actions.get && !!this.actions.save;
+            const hasDelete   = !!this.actions.delete;
+
+            return `
+<div class="jfm-card${enabled ? '' : ' jfm-off'}" data-jfm-file="${filename}">
+  <div class="jfm-card-top">
+    <span class="jfm-card-name" title="${filename}">${displayName}</span>
+    ${showToggle ? `
+    <label class="jfm-toggle" title="${enabled ? 'Enabled — click to disable' : 'Disabled — click to enable'}">
+      <input type="checkbox" class="jfm-toggle-cb" data-cat="${catName}" ${enabled ? 'checked' : ''}>
+      <span>${enabled ? 'On' : 'Off'}</span>
+    </label>` : ''}
+  </div>
+  <div class="jfm-card-meta">
+    <span>&#128196; ${filename}</span>
+    <span>&#128202; ${f.entry_count ?? 0} entries &middot; ${this._fmtSize(f.size || 0)}</span>
+    <span>&#128337; ${this._fmtDate(f.modified)}</span>
+  </div>
+  <div class="jfm-card-actions">
+    ${hasEdit ? `<button class="jfm-btn jfm-btn-sm" data-jfm="edit-file">&#9998; Edit</button>` : ''}
+    ${hasDelete ? `<button class="jfm-btn jfm-btn-danger jfm-btn-sm jfm-del" data-jfm="del-file" title="Delete file">&#128465;</button>` : ''}
+  </div>
+</div>`;
+        }
+
+        // ── Edit flow ────────────────────────────────────────────────────────
+
+        async _openEdit(filename) {
+            this._editFile = filename;
+            document.getElementById(`${this._uid}-edit-title`).textContent = `Edit: ${filename}`;
+            this._clearErr();
+            this._editorEl.value = 'Loading…';
+            this._updateStat();
+            this._editModal.hidden = false;
+
+            try {
+                const data = await this._api('get', { filename });
+                if (data.status !== 'success') throw new Error(data.message || 'Load failed');
+                this._editorEl.value = JSON.stringify(data.content, null, 2);
+                this._updateStat();
+                this._editorEl.focus();
+                this._editorEl.setSelectionRange(0, 0);
+                this._editorEl.scrollTop = 0;
+            } catch (err) {
+                this._showErr('Failed to load file: ' + err.message);
+                this._editorEl.value = '';
+            }
+        }
+
+        _closeEdit() {
+            if (this._editModal) this._editModal.hidden = true;
+            this._editFile = null;
+            this._clearErr();
+        }
+
+        _formatJson() {
+            try {
+                const parsed = JSON.parse(this._editorEl.value);
+                this._editorEl.value = JSON.stringify(parsed, null, 2);
+                this._updateStat();
+                this._clearErr();
+            } catch (err) {
+                this._showErr('Invalid JSON — ' + err.message);
+            }
+        }
+
+        _validateJson() {
+            try {
+                const parsed = JSON.parse(this._editorEl.value);
+                const n = (typeof parsed === 'object' && parsed !== null) ? Object.keys(parsed).length : '?';
+                this._clearErr();
+                this._notify(`Valid JSON — ${n} top-level keys`, 'success');
+            } catch (err) {
+                this._showErr('Invalid JSON — ' + err.message);
+            }
+        }
+
+        async _doSave() {
+            if (!this._editFile) return;
+            let contentStr;
+            try {
+                const parsed = JSON.parse(this._editorEl.value);
+                contentStr = JSON.stringify(parsed, null, 2);
+            } catch (err) {
+                this._showErr('Cannot save — fix JSON first: ' + err.message);
+                return;
+            }
+            const btn = document.getElementById(`${this._uid}-save-btn`);
+            this._busy(btn, 'Saving…');
+            try {
+                const data = await this._api('save', { filename: this._editFile, content: contentStr });
+                if (data.status !== 'success') throw new Error(data.message || 'Save failed');
+                this._notify('File saved', 'success');
+                this._closeEdit();
+                this._loadList();
+            } catch (err) {
+                this._showErr('Save failed: ' + err.message);
+                this._idle(btn, 'Save');
+            }
+        }
+
+        // ── Delete flow ──────────────────────────────────────────────────────
+
+        _openDel(filename) {
+            this._deleteFile = filename;
+            const el = document.getElementById(`${this._uid}-del-name`);
+            if (el) el.textContent = filename;
+            if (this._delModal) this._delModal.hidden = false;
+        }
+
+        _closeDel() {
+            if (this._delModal) this._delModal.hidden = true;
+            this._deleteFile = null;
+        }
+
+        async _doDelete() {
+            if (!this._deleteFile) return;
+            const btn = document.getElementById(`${this._uid}-del-btn`);
+            this._busy(btn, 'Deleting…');
+            try {
+                const data = await this._api('delete', { filename: this._deleteFile });
+                if (data.status !== 'success') throw new Error(data.message || 'Delete failed');
+                this._notify('File deleted', 'success');
+                this._closeDel();
+                this._loadList();
+            } catch (err) {
+                this._notify('Delete failed: ' + err.message, 'error');
+                this._idle(btn, 'Delete');
+            }
+        }
+
+        // ── Create flow ──────────────────────────────────────────────────────
+
+        _openCreate() {
+            if (!this._createModal) return;
+            this.createFields.forEach(f => {
+                const el = document.getElementById(`${this._uid}-cf-${f.key}`);
+                if (el) el.value = '';
+            });
+            this._createModal.hidden = false;
+            const first = this.createFields[0];
+            if (first) document.getElementById(`${this._uid}-cf-${first.key}`)?.focus();
+        }
+
+        _closeCreate() {
+            if (this._createModal) this._createModal.hidden = true;
+        }
+
+        async _doCreate() {
+            const params = {};
+            for (const f of this.createFields) {
+                const el  = document.getElementById(`${this._uid}-cf-${f.key}`);
+                const val = (el?.value || '').trim();
+                if (!val) {
+                    this._notify(`"${f.label}" is required`, 'error');
+                    el?.focus();
+                    return;
+                }
+                if (f.pattern && !new RegExp(f.pattern).test(val)) {
+                    this._notify(`"${f.label}" format is invalid`, 'error');
+                    el?.focus();
+                    return;
+                }
+                params[f.key] = val;
+            }
+            // Auto-derive display_name from category_name if left blank
+            const nameField = this.createFields.find(f => f.key === 'display_name');
+            if (nameField) {
+                const el = document.getElementById(`${this._uid}-cf-display_name`);
+                if (el && !el.value.trim()) {
+                    const catEl = document.getElementById(`${this._uid}-cf-category_name`);
+                    if (catEl?.value) {
+                        params.display_name = catEl.value.replace(/_/g, ' ').replace(/\b\w/g, c => c.toUpperCase());
+                    }
+                }
+            }
+            const btn = document.getElementById(`${this._uid}-create-btn`);
+            this._busy(btn, 'Creating…');
+            try {
+                const data = await this._api('create', params);
+                if (data.status !== 'success') throw new Error(data.message || 'Create failed');
+                this._notify('File created', 'success');
+                this._closeCreate();
+                this._loadList();
+            } catch (err) {
+                this._notify('Create failed: ' + err.message, 'error');
+                this._idle(btn, 'Create');
+            }
+        }
+
+        // ── Upload ───────────────────────────────────────────────────────────
+
+        async _uploadFile(file) {
+            if (!file.name.endsWith('.json')) {
+                this._notify('Please select a .json file', 'error');
+                return;
+            }
+            let content;
+            try {
+                content = await file.text();
+                JSON.parse(content); // client-side validation
+            } catch (err) {
+                this._notify('Invalid JSON: ' + err.message, 'error');
+                return;
+            }
+            if (this._dropzone) this._dropzone.style.opacity = '.5';
+            try {
+                const data = await this._api('upload', { filename: file.name, content });
+                if (data.status !== 'success') throw new Error(data.message || 'Upload failed');
+                this._notify(`"${file.name}" uploaded`, 'success');
+                this._loadList();
+            } catch (err) {
+                this._notify('Upload failed: ' + err.message, 'error');
+            } finally {
+                if (this._dropzone) this._dropzone.style.opacity = '';
+            }
+        }
+
+        // ── Toggle ───────────────────────────────────────────────────────────
+
+        async _doToggle(catName, enabled, checkbox) {
+            checkbox.disabled = true;
+            try {
+                const params = { enabled };
+                if (this.toggleKey) params[this.toggleKey] = catName;
+                const data = await this._api('toggle', params);
+                if (data.status !== 'success') throw new Error(data.message || 'Toggle failed');
+                this._notify(enabled ? 'Category enabled' : 'Category disabled', 'success');
+                this._loadList();
+            } catch (err) {
+                this._notify('Toggle failed: ' + err.message, 'error');
+                checkbox.checked = !enabled; // revert
+                checkbox.disabled = false;
+            }
+        }
+
+        // ── Helpers ──────────────────────────────────────────────────────────
+
+        _closeAll() {
+            this._closeEdit();
+            this._closeDel();
+            this._closeCreate();
+        }
+
+        _updateStat() {
+            const v = this._editorEl?.value || '';
+            const lines = v ? v.split('\n').length : 0;
+            const el = document.getElementById(`${this._uid}-charcount`);
+            if (el) el.textContent = `${lines.toLocaleString()} lines · ${v.length.toLocaleString()} chars`;
+        }
+
+        _showErr(msg) {
+            const el = document.getElementById(`${this._uid}-edit-err`);
+            if (el) { el.textContent = msg; el.hidden = false; }
+        }
+
+        _clearErr() {
+            const el = document.getElementById(`${this._uid}-edit-err`);
+            if (el) { el.textContent = ''; el.hidden = true; }
+        }
+
+        _notify(msg, type) {
+            if (typeof window.showNotification === 'function') {
+                window.showNotification(msg, type || 'info');
+            } else {
+                console.info(`[JsonFileManager] ${type || 'info'}: ${msg}`);
+            }
+        }
+
+        _busy(btn, label) {
+            if (!btn) return;
+            btn._jfmOriginal = btn.innerHTML;
+            btn.disabled = true;
+            btn.innerHTML = `<span class="jfm-spin"></span> ${this._esc(label)}`;
+        }
+
+        _idle(btn, label) {
+            if (!btn) return;
+            btn.disabled = false;
+            btn.innerHTML = btn._jfmOriginal || this._esc(label);
+        }
+
+        _esc(str) {
+            const d = document.createElement('div');
+            d.textContent = String(str ?? '');
+            return d.innerHTML;
+        }
+
+        _fmtSize(bytes) {
+            if (!bytes) return '0 B';
+            const i = Math.min(Math.floor(Math.log2(bytes + 1) / 10), 2);
+            const unit = ['B', 'KB', 'MB'][i];
+            const val  = bytes / Math.pow(1024, i);
+            return (i ? val.toFixed(1) : val) + ' ' + unit;
+        }
+
+        _fmtDate(str) {
+            if (!str) return '—';
+            try {
+                return new Date(str).toLocaleDateString(undefined, {
+                    month: 'short', day: 'numeric', year: 'numeric'
+                });
+            } catch { return str; }
+        }
+    }
+
+    // ── Widget registry integration ──────────────────────────────────────────
+
+    window.JsonFileManager = JsonFileManager;
+
+    if (typeof window.LEDMatrixWidgets !== 'undefined') {
+        window.LEDMatrixWidgets.register('json-file-manager', {
+            name: 'JSON File Manager',
+            version: '1.0.0',
+            render(container, config, _value, options) {
+                new JsonFileManager(container, config || {}, options?.pluginId || '');
+            },
+            getValue() { return null; },
+            setValue() {}
+        });
+        console.log('[JsonFileManager] Registered with LEDMatrixWidgets');
+    } else {
+        console.log('[JsonFileManager] Loaded (LEDMatrixWidgets registry not available)');
+    }
+})();

web_interface/static/v3/plugins_manager.js

@@ -3446,6 +3446,23 @@ function generateFieldHtml(key, prop, value, prefix = '') {
             html += `<option value="${option}" ${selected}>${option}</option>`;
         });
         html += `</select>`;
+    } else if (prop['x-widget'] === 'json-file-manager') {
+        // Reusable JSON file manager widget (no CDN, keyboard shortcuts, configurable actions)
+        const widgetConfig = prop['x-widget-config'] || {};
+        const pluginId = currentPluginConfig?.pluginId || window.currentPluginConfig?.pluginId || '';
+        const safeFieldId = (fullKey || 'file_manager').replace(/[^a-zA-Z0-9_-]/g, '_');
+
+        html += `<div id="${safeFieldId}_jfm_mount"></div>`;
+
+        setTimeout(() => {
+            const mount = document.getElementById(`${safeFieldId}_jfm_mount`);
+            if (!mount) return;
+            if (typeof JsonFileManager !== 'undefined') {
+                new JsonFileManager(mount, widgetConfig, pluginId);
+            } else {
+                mount.innerHTML = '<p style="color:#dc2626;font-size:.875rem;">json-file-manager widget not loaded. Check base.html includes json-file-manager.js.</p>';
+            }
+        }, 150);
     } else if (prop['x-widget'] === 'custom-html') {
         // Custom HTML widget - load HTML from plugin directory
         const htmlFile = prop['x-html-file'];

web_interface/templates/v3/base.html

@@ -1370,34 +1370,64 @@
 
     <!-- SSE connection for real-time updates -->
     <script>
-        // Connect to SSE streams
-        const statsSource = new EventSource('/api/v3/stream/stats');
-        const displaySource = new EventSource('/api/v3/stream/display');
+        // Assign to window so reconnectSSE() in app.js can reach them.
+        window.statsSource = new EventSource('/api/v3/stream/stats');
+        window.displaySource = new EventSource('/api/v3/stream/display');
 
-        statsSource.onmessage = function(event) {
+        window.statsSource.onmessage = function(event) {
             const data = JSON.parse(event.data);
             updateSystemStats(data);
         };
 
-        displaySource.onmessage = function(event) {
+        window.displaySource.onmessage = function(event) {
             const data = JSON.parse(event.data);
             updateDisplayPreview(data);
         };
 
-        // Connection status
-        statsSource.addEventListener('open', function() {
-            document.getElementById('connection-status').innerHTML = `
-                <div class="w-2 h-2 bg-green-500 rounded-full"></div>
-                <span class="text-gray-600">Connected</span>
-            `;
-        });
+        function _setConnectionStatus(connected, reconnecting) {
+            const el = document.getElementById('connection-status');
+            if (!el) return;
+            if (connected) {
+                el.innerHTML = `
+                    <div class="w-2 h-2 bg-green-500 rounded-full"></div>
+                    <span class="text-gray-600">Connected</span>
+                `;
+            } else if (reconnecting) {
+                el.innerHTML = `
+                    <div class="w-2 h-2 bg-yellow-500 rounded-full animate-pulse"></div>
+                    <span class="text-gray-600">Reconnecting…</span>
+                `;
+            } else {
+                el.innerHTML = `
+                    <div class="w-2 h-2 bg-red-500 rounded-full"></div>
+                    <span class="text-gray-600" title="Connection lost — try refreshing the page">Disconnected</span>
+                `;
+            }
+        }
 
-        statsSource.addEventListener('error', function() {
-            document.getElementById('connection-status').innerHTML = `
-                <div class="w-2 h-2 bg-red-500 rounded-full"></div>
-                <span class="text-gray-600">Disconnected</span>
-            `;
-        });
+        var _statsErrorCount = 0;
+
+        // Named on window so reconnectSSE() in app.js can reattach them after
+        // replacing the EventSource instances.
+        window._statsOpenHandler = function() {
+            _statsErrorCount = 0;
+            _setConnectionStatus(true, false);
+        };
+        window._statsErrorHandler = function() {
+            _statsErrorCount++;
+            // EventSource readyState 0 = CONNECTING (auto-retrying), 2 = CLOSED
+            var reconnecting = window.statsSource.readyState === EventSource.CONNECTING;
+            _setConnectionStatus(false, reconnecting && _statsErrorCount <= 3);
+        };
+        window._displayErrorHandler = function() {
+            // Display stream errors don't change the status badge but log to console
+            // so failures aren't completely silent.
+            console.warn('LEDMatrix: display preview stream error (readyState=' + window.displaySource.readyState + ')');
+        };
+
+        window.statsSource.addEventListener('open', window._statsOpenHandler);
+        window.statsSource.addEventListener('error', window._statsErrorHandler);
+        window.displaySource.addEventListener('error', window._displayErrorHandler);
 
         function updateSystemStats(data) {
             // Update CPU in header
@@ -4595,6 +4625,9 @@
     <script src="{{ url_for('static', filename='v3/js/widgets/timezone-selector.js') }}" defer></script>
     <script src="{{ url_for('static', filename='v3/js/widgets/plugin-loader.js') }}" defer></script>
     
+    <!-- Reusable JSON file manager widget (used by of-the-day and others via x-widget: json-file-manager) -->
+    <script src="{{ url_for('static', filename='v3/js/widgets/json-file-manager.js') }}" defer></script>
+
     <!-- Legacy plugins_manager.js (for backward compatibility during migration) -->
     <script src="{{ url_for('static', filename='v3/plugins_manager.js') }}?v=20260307" defer></script>