fix(backend): remove broken remote branch in /api/system/stats

The remoteNodeProxy middleware (line 373) is already positioned before
all API route definitions, so remote requests are correctly proxied to
the target Sencho instance before any route handler executes.

However, /api/system/stats had a dead remote branch that called
NodeRegistry.getDocker() for remote nodes. This method throws by design
("remote nodes are not directly accessible") since no direct Docker TCP
socket is used for remote nodes. The thrown error propagated through the
catch block, returning a 500 to the frontend and causing system stats to
show as loading/unavailable for remote nodes.

Removed the dead branch. Remote requests for /api/system/stats are now
correctly proxied, returning real CPU/RAM/disk data from the remote host.

backend/src/index.ts

@@ -1139,35 +1139,11 @@ app.get('/api/logs/global/stream', async (req: Request, res: Response) => {
 // Get host system stats
 app.get('/api/system/stats', async (req: Request, res: Response) => {
   try {
-    const nodeId = req.nodeId ?? NodeRegistry.getInstance().getDefaultNodeId();
-    const node = NodeRegistry.getInstance().getNode(nodeId);
-
     const rxSec = Math.max(0, globalDockerNetwork.rxSec);
     const txSec = Math.max(0, globalDockerNetwork.txSec);
 
-    if (node && node.type === 'remote') {
-      // Remote node: use Docker daemon info for CPU/RAM - disk is not available via Docker API
-      const docker = NodeRegistry.getInstance().getDocker(nodeId);
-      const info = await docker.info();
-
-      res.json({
-        cpu: {
-          usage: '0',
-          cores: info.NCPU ?? 0,
-        },
-        memory: {
-          total: info.MemTotal ?? 0,
-          used: 0,
-          free: info.MemTotal ?? 0,
-          usagePercent: '0',
-        },
-        disk: null,
-        network: { rxBytes: 0, txBytes: 0, rxSec, txSec },
-      });
-      return;
-    }
-
-    // Local node: use systeminformation for accurate host metrics
+    // Remote node requests are intercepted and proxied by remoteNodeProxy before reaching here.
+    // This handler only runs for local nodes.
     const [currentLoad, mem, fsSize] = await Promise.all([
       si.currentLoad(),
       si.mem(),