Add debug logging for file identity

app/src/main/java/com/nexlab/openclaw/node/data/remote/NodeClient.kt

@@ -94,7 +94,10 @@ class NodeClient() {
         
         // Use a file instead of SharedPreferences to ensure it works across processes
         // SharedPreferences are not shared between processes by default
-        val identityFile = context?.let { File(it.filesDir, "device_identity.json") }
+        val filesDir = context?.filesDir
+        Log.d(TAG, "filesDir: $filesDir")
+        val identityFile = filesDir?.let { File(it, "device_identity.json") }
+        Log.d(TAG, "identityFile: $identityFile, exists: ${identityFile?.exists()}")
         
         if (identityFile?.exists() == true) {
             try {