Add WebSocket observer endpoint for hub state monitoring

- Add /ws/observe WebSocket path for real-time hub state observation
- Implement setupObserveServer(httpServer) function that:
  - Requires secret authentication via observe handshake
  - Sends immediate snapshot of backends on successful auth
  - Streams all EventBus events to connected observers
  - Maintains read-only connections (ignores post-handshake messages)
  - Properly cleans up listeners on disconnect
- Add OBSERVE_SECRET to .env (generate with crypto.randomBytes)
- Export OBSERVE_SECRET from config.js
- Wire setupObserveServer into index.js alongside existing setupWsServer
- Support multiple simultaneous observers
- Modified ws-server.js to allow other upgrade handlers (ws-observe, etc)
- Add OBSERVE_SECRET to ecosystem.config.js env for pm2

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

ecosystem.config.js

@@ -3,6 +3,9 @@ require('dotenv').config({ path: __dirname + '/.env' });
 const HUB_SECRET = process.env.HUB_SECRET;
 if (!HUB_SECRET) throw new Error('HUB_SECRET not set in .env');
 
+const OBSERVE_SECRET = process.env.OBSERVE_SECRET;
+if (!OBSERVE_SECRET) throw new Error('OBSERVE_SECRET not set in .env');
+
 module.exports = {
   apps: [
     {
@@ -12,7 +15,11 @@ module.exports = {
       env: {
         NODE_ENV: 'development',
         PORT: 3000,
-        HUB_AUTH: JSON.stringify({ 'sample-mcp': HUB_SECRET, 'memory-mcp': HUB_SECRET })
+        HUB_AUTH: JSON.stringify({ 'sample-mcp': HUB_SECRET, 'memory-mcp': HUB_SECRET }),
+        OBSERVE_SECRET: OBSERVE_SECRET,
+        GOOGLE_CLIENT_ID: process.env.GOOGLE_CLIENT_ID || '',
+        GOOGLE_CLIENT_SECRET: process.env.GOOGLE_CLIENT_SECRET || '',
+        OAUTH_ISSUER: process.env.OAUTH_ISSUER || 'https://mcp.arik.work'
       },
       max_restarts: 10,
       restart_delay: 1000,