feat: Add presence heartbeat for Matrix online status

- matrix-gateway: POST /internal/matrix/presence/online endpoint
- usePresenceHeartbeat hook with activity tracking
- Auto away after 5 min inactivity
- Offline on page close/visibility change
- Integrated in MatrixChatRoom component

node-network-app/vite.config.ts

@@ -0,0 +1,29 @@
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+
+export default defineConfig({
+  plugins: [react()],
+  server: {
+    port: 3000,
+    open: true,
+    proxy: {
+      '/api/node-metrics': {
+        target: 'http://localhost:9205',
+        changeOrigin: true,
+      },
+      '/api/v1/nodes': {
+        target: 'http://localhost:9205',
+        changeOrigin: true,
+        rewrite: (path) => path.replace(/^\/api\/v1/, '/api/v1'),
+      },
+      '/api/metrics': {
+        target: 'http://localhost:9205',
+        changeOrigin: true,
+      },
+      '/api': {
+        target: 'http://localhost:9205',
+        changeOrigin: true,
+      },
+    },
+  },
+});