Add LLM configuration and MCP server management UI and backend functionality

- Implemented a new SPA page for LLM Bridge and MCP Server settings in `llm-config.js`.
- Added functionality for managing LLM and MCP configurations, including toggling, saving settings, and testing connections.
- Created HTTP endpoints in `llm_utils.py` for handling LLM chat, status checks, and MCP server configuration.
- Integrated model fetching from LaRuche and Ollama backends.
- Enhanced error handling and logging for better debugging and user feedback.

web/js/core/resource-tracker.js

@@ -45,6 +45,11 @@ export class ResourceTracker {
     this._listeners.push({ target, event, handler, options });
   }
 
+  /** Shorthand alias for trackEventListener. */
+  on(target, event, handler, options) {
+    return this.trackEventListener(target, event, handler, options);
+  }
+
   /* -- AbortControllers (for fetch) -- */
   trackAbortController() {
     const ac = new AbortController();