fix: add capability check to perf daemon handler

The perf handler was missing an isCommandSupportedOnDevice check,
so it returned empty metrics instead of UNSUPPORTED_OPERATION for
platforms where perf is not supported (e.g. harmonyos).

Author: wangcz

src/daemon/handlers/session-observability.ts

@@ -74,6 +74,9 @@ async function handlePerfCommand(params: ObservabilityParams): Promise<DaemonRes
   if (!session) {
     return errorResponse('SESSION_NOT_FOUND', 'perf requires an active session. Run open first.');
   }
+  if (!isCommandSupportedOnDevice('perf', session.device)) {
+    return errorResponse('UNSUPPORTED_OPERATION', 'perf is not supported on this device');
+  }
 
   try {
     return {