docs: fix bare /api/plugins paths in PLUGIN_CONFIGURATION_TABS

Found 5 more bare /api/plugins/* paths in PLUGIN_CONFIGURATION_TABS.md
that I missed in the round 2 sweep — they're inside data flow diagrams
and prose ("loaded via /api/plugins/installed", etc.) so the earlier
grep over Markdown code blocks didn't catch them. Fixed all 5 to use
/api/v3/plugins/* (the api_v3 blueprint mount path verified at
web_interface/app.py:144).

Also added a status banner noting that the "Implementation Details"
section references the pre-v3 file layout (web_interface_v2.py,
templates/index_v2.html) which no longer exists. The current
implementation is in web_interface/app.py, blueprints/api_v3.py, and
templates/v3/. Same kind of historical drift I flagged in
PLUGIN_ARCHITECTURE_SPEC.md and the PLUGIN_CUSTOM_ICONS_FEATURE doc.
The user-facing parts of the doc (Overview, Features, Form Generation
Process) are still accurate.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/PLUGIN_CONFIGURATION_TABS.md

@@ -1,5 +1,15 @@
 # Plugin Configuration Tabs
 
+> **Status note:** this doc was written during the rollout of the
+> per-plugin configuration tab feature. The feature itself is shipped
+> and working in the current v3 web interface, but a few file paths
+> in the "Implementation Details" section below still reference the
+> pre-v3 file layout (`web_interface_v2.py`, `templates/index_v2.html`).
+> The current implementation lives in `web_interface/app.py`,
+> `web_interface/blueprints/api_v3.py`, and `web_interface/templates/v3/`.
+> The user-facing description (Overview, Features, Form Generation
+> Process) is still accurate.
+
 ## Overview
 
 Each installed plugin now gets its own dedicated configuration tab in the web interface. This provides a clean, organized way to configure plugins without cluttering the main Plugins management tab.
@@ -198,12 +208,12 @@ Renders as: Dropdown select
 
 ### Form Generation Process
 
-1. Web UI loads installed plugins via `/api/plugins/installed`
+1. Web UI loads installed plugins via `/api/v3/plugins/installed`
 2. For each plugin, the backend loads its `config_schema.json`
 3. Frontend generates a tab button with plugin name
 4. Frontend generates a form based on the JSON Schema
 5. Current config values from `config.json` are populated
-6. When saved, each field is sent to `/api/plugins/config` endpoint
+6. When saved, each field is sent to `/api/v3/plugins/config` endpoint
 
 ## Implementation Details
 
@@ -211,7 +221,7 @@ Renders as: Dropdown select
 
 **File**: `web_interface_v2.py`
 
-- Modified `/api/plugins/installed` endpoint to include `config_schema_data`
+- Modified `/api/v3/plugins/installed` endpoint to include `config_schema_data`
 - Loads each plugin's `config_schema.json` if it exists
 - Returns schema data along with plugin info
 
@@ -231,7 +241,7 @@ New Functions:
 ```
 Page Load
   → refreshPlugins()
-    → /api/plugins/installed
+    → /api/v3/plugins/installed
       → Returns plugins with config_schema_data
     → generatePluginTabs()
       → Creates tab buttons
@@ -245,7 +255,7 @@ User Saves
   → savePluginConfiguration()
     → Reads form data
     → Converts types per schema
-    → Sends to /api/plugins/config
+    → Sends to /api/v3/plugins/config
       → Updates config.json
     → Shows success notification
 ```