fix(plugins): web mode lookups use the modes the display registered (#668)

A plugin may compute its display modes from its config: soccer-scoreboard
registers soccer_<league>_live/recent/upcoming for every custom_leagues
entry, which no manifest can list ahead of time. The display always rotated
them (_register_loaded_plugin prefers plugin.modes), but the web process
reads plugins as files, so /display/modes, the on-demand dialog and
on-demand/start with a mode and no plugin_id saw only manifests -- a custom
league's mode was missing from every list and 404'd on lookup.

- PluginStateManager.record_modes(): the controller records what it
  registered, on the loaded record (an unload or reload forgets it)
- the runtime snapshot carries it per plugin as "modes" (bounded), and
  PluginRuntimeView.display_modes() reports it only while live
- PluginCatalog takes a runtime_source; get_plugin_display_modes and
  find_plugin_for_mode prefer the live modes, falling back to the manifest
  when the display is stopped or has not loaded the plugin. The view is read
  at most once a second, so a listing is one read, not one per plugin.

No manifest or plugin change needed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/plugin_system/plugin_runtime.py

@@ -56,7 +56,7 @@ import os
 import threading
 import time
 from dataclasses import dataclass, field, replace
-from typing import Any, Callable, Dict, Optional
+from typing import Any, Callable, Dict, List, Optional
 
 from src import display_watchdog
 from src.logging_config import get_logger
@@ -100,6 +100,9 @@ _ERROR_MESSAGE_CHARS = 200
 _ERROR_TYPE_CHARS = 80
 _ID_CHARS = 100
 _VERSION_CHARS = 40
+#: Bounds on a plugin's published ``modes``: a plugin computes them, so a
+#: runaway list must not bloat a file written to the SD card.
+_MAX_MODES = 200
 
 #: Reader statuses. Only LIVE carries runtime facts.
 LIVE = "live"
@@ -154,6 +157,13 @@ def summarize_error(error_info: Optional[Dict[str, Any]]) -> Optional[Dict[str,
     }
 
 
+def _published_modes(modes: Any) -> Optional[List[str]]:
+    """The registered display modes as a snapshot carries them, or None."""
+    if not isinstance(modes, list):
+        return None
+    return [_clip(m, _ID_CHARS) for m in modes[:_MAX_MODES] if isinstance(m, str)]
+
+
 def build_runtime_snapshot(state_manager: Any, *, started_at: float,
                            now: Optional[float] = None,
                            running: bool = True,
@@ -173,6 +183,7 @@ def build_runtime_snapshot(state_manager: Any, *, started_at: float,
                 "error": summarize_error(record.get("error_info")),
                 "version": _clip(version, _VERSION_CHARS) if version else None,
                 "loaded_at": _epoch(record.get("loaded_at")),
+                "modes": _published_modes(record.get("modes")),
             }
     return {
         "schema": SNAPSHOT_SCHEMA,
@@ -416,6 +427,21 @@ class PluginRuntimeView:
             "loaded_at": record.get("loaded_at"),
         }
 
+    def display_modes(self, plugin_id: str) -> Optional[List[str]]:
+        """The display modes the display registered for ``plugin_id``: what
+        it rotates and accepts on-demand, including modes a plugin computes
+        from its config. None unless the view is live and the plugin is
+        loaded with its modes registered -- the caller then falls back to
+        the manifest's ``display_modes``."""
+        if not self.live:
+            return None
+        record = self.plugins.get(plugin_id)
+        modes = record.get("modes") if isinstance(record, dict) else None
+        if not isinstance(modes, list):
+            return None
+        modes = [m for m in modes if isinstance(m, str)]
+        return modes or None
+
     def describe(self) -> Dict[str, Any]:
         """The view's own status, for a response to carry beside the facts."""
         return {