feat: implement FastAPI router, web + local UI updates, and metadata monitoring for the edge node

drb-edge-node/app/internal/metadata_watcher.py

@@ -123,6 +123,10 @@ class MetadataWatcher:
     def current_tgid(self) -> Optional[int]:
         return self._current_tgid
 
+    @property
+    def current_tgid_name(self) -> Optional[str]:
+        return self._current_tgid_name
+
     @property
     def is_active(self) -> bool:
         return self._active_call_id is not None