FRE-600: Fix code review blockers

- Consolidated duplicate UndoManagers to single instance
- Fixed connection promise to only resolve on 'connected' status
- Fixed WebSocketProvider import (WebsocketProvider)
- Added proper doc.destroy() cleanup
- Renamed isPresenceInitialized property to avoid conflict

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/lib/collaboration/presence-manager.ts

@@ -155,14 +155,10 @@ export class PresenceManager {
     this.provider = connection.getProvider();
     
     // Listen for Yjs awareness updates (y-websocket uses awareness for presence)
-    this.provider.on('awareness', (event: { states: Map<number, any> }) => {
-      this.processAwarenessUpdate(event.states);
-    });
+    this.provider.on('awareness', this.handleAwarenessUpdate);
     
     // Listen for generic message events for custom presence messages
-    this.provider.on('message', (event: { message: PresenceMessage }) => {
-      this.processPresenceMessage(event.message);
-    });
+    this.provider.on('message', this.handlePresenceMessage);
     
     // Start idle monitoring
     this.startIdleMonitor();
@@ -571,7 +567,3 @@ export const DEFAULT_USER_COLORS = [
   '#6366f1', // indigo
   '#14b8a6', // teal
 ];
-
-</content>
-<parameter=filePath>
-/home/mike/code/FrenoCorp/src/lib/collaboration/presence-manager.ts