feat: enhance health check endpoints with Socket.IO monitoring

- Enhanced /api/health endpoint
  - Added Socket.IO status monitoring (engine status, client count, active sockets)
  - Added memory usage metrics (heap used, heap total, RSS)
  - Returns 503 (degraded) if either CouchDB or Socket.IO is down
  - Restructured response with nested 'services' object for better clarity

- Added dedicated /api/health/socketio endpoint
  - Provides detailed Socket.IO connection information
  - Shows connected clients and active sockets count
  - Lists active rooms (event_ and post_ rooms) with member counts
  - Useful for debugging real-time connection issues

Benefits:
- Better observability for Kubernetes health probes
- Can monitor Socket.IO connection health separately from database
- Helps diagnose real-time feature issues
- Memory metrics useful for detecting leaks on resource-constrained Raspberry Pi nodes

Response Format:
GET /api/health
{
  "status": "healthy",
  "timestamp": "...",
  "uptime": 123.45,
  "services": {
    "couchdb": "connected",
    "socketIO": {
      "status": "running",
      "connectedClients": 5,
      "activeSockets": 5
    }
  },
  "memory": { ... }
}

GET /api/health/socketio
{
  "status": "running",
  "connectedClients": 5,
  "activeSockets": 5,
  "rooms": [
    { "name": "event_123", "members": 3 },
    { "name": "post_456", "members": 2 }
  ]
}

🤖 Generated with AI Assistant

Co-Authored-By: AI Assistant <noreply@ai-assistant.com>

backend/server.js

@@ -147,23 +147,82 @@ app.get("/api/health", async (req, res) => {
   try {
     const couchdbStatus = await couchdbService.checkConnection();
     
-    res.status(200).json({
-      status: "healthy",
+    // Check Socket.IO status
+    const socketIOStatus = {
+      engine: io.engine ? "running" : "stopped",
+      connectedClients: io.engine ? io.engine.clientsCount : 0,
+      // Get number of connected sockets
+      sockets: io.sockets ? io.sockets.sockets.size : 0
+    };
+    
+    const isHealthy = couchdbStatus && io.engine;
+    
+    res.status(isHealthy ? 200 : 503).json({
+      status: isHealthy ? "healthy" : "degraded",
       timestamp: new Date().toISOString(),
       uptime: process.uptime(),
-      couchdb: couchdbStatus ? "connected" : "disconnected",
+      services: {
+        couchdb: couchdbStatus ? "connected" : "disconnected",
+        socketIO: {
+          status: socketIOStatus.engine,
+          connectedClients: socketIOStatus.connectedClients,
+          activeSockets: socketIOStatus.sockets
+        }
+      },
+      memory: {
+        heapUsed: Math.round(process.memoryUsage().heapUsed / 1024 / 1024) + " MB",
+        heapTotal: Math.round(process.memoryUsage().heapTotal / 1024 / 1024) + " MB",
+        rss: Math.round(process.memoryUsage().rss / 1024 / 1024) + " MB"
+      }
     });
   } catch (error) {
     res.status(503).json({
       status: "unhealthy",
       timestamp: new Date().toISOString(),
       uptime: process.uptime(),
-      couchdb: "disconnected",
+      services: {
+        couchdb: "disconnected",
+        socketIO: "unknown"
+      },
       error: error.message,
     });
   }
 });
 
+// Detailed Socket.IO health check endpoint
+app.get("/api/health/socketio", (req, res) => {
+  try {
+    const socketIOInfo = {
+      status: io.engine ? "running" : "stopped",
+      connectedClients: io.engine ? io.engine.clientsCount : 0,
+      activeSockets: io.sockets ? io.sockets.sockets.size : 0,
+      rooms: [],
+      timestamp: new Date().toISOString()
+    };
+
+    // Get list of active rooms (excluding auto-generated socket ID rooms)
+    if (io.sockets && io.sockets.adapter && io.sockets.adapter.rooms) {
+      const rooms = Array.from(io.sockets.adapter.rooms.keys()).filter(room => {
+        // Filter out socket ID rooms (they start with socket ID pattern)
+        return room.startsWith('event_') || room.startsWith('post_');
+      });
+      
+      socketIOInfo.rooms = rooms.map(room => {
+        const roomSize = io.sockets.adapter.rooms.get(room)?.size || 0;
+        return { name: room, members: roomSize };
+      });
+    }
+
+    res.status(200).json(socketIOInfo);
+  } catch (error) {
+    res.status(500).json({
+      status: "error",
+      error: error.message,
+      timestamp: new Date().toISOString()
+    });
+  }
+});
+
 // Routes
 app.use("/api/auth", authRoutes);
 app.use("/api/streets", streetRoutes);