fix session routing and subagent visibility

backend/api/server.py

@@ -1659,7 +1659,10 @@ def create_app(state: AgentState) -> FastAPI:
 
     # ------------- sessions --------------------------------------------------
     @app.get('/api/sessions')
-    async def list_sessions(account_id: str | None = None) -> list[dict[str, Any]]:
+    async def list_sessions(
+        account_id: str | None = None,
+        include_children: bool = False,
+    ) -> list[dict[str, Any]]:
         directory = state.account_paths(account_id)['sessions']
         if not directory.exists():
             return []
@@ -1670,6 +1673,16 @@ def create_app(state: AgentState) -> FastAPI:
             except (OSError, json.JSONDecodeError):
                 continue
             session_id = str(data.get('session_id', _session_id_from_path(path)))
+            session_metadata = (
+                data.get('session_metadata')
+                if isinstance(data.get('session_metadata'), dict)
+                else {}
+            )
+            if (
+                not include_children
+                and session_metadata.get('visibility') == 'child'
+            ):
+                continue
             usage = data.get('usage') if isinstance(data.get('usage'), dict) else {}
             model_config = (
                 data.get('model_config')
@@ -1695,6 +1708,7 @@ def create_app(state: AgentState) -> FastAPI:
                     'model': model_config.get('model'),
                     'usage': usage,
                     'is_training': bool(data.get('is_training', False)),
+                    'session_metadata': session_metadata,
                 }
             )
         return results
@@ -2769,6 +2783,7 @@ def _serialize_stored_session(stored: StoredAgentSession) -> dict[str, Any]:
         'total_cost_usd': stored.total_cost_usd,
         'model': stored.model_config.get('model'),
         'is_training': stored.is_training,
+        'session_metadata': stored.session_metadata or {},
     }