feat: implement Swapper metrics collection and UI

services/city-service/routes_city.py

@@ -4057,6 +4057,52 @@ async def get_node_self_healing_status(node_id: str):
         )
 
 
+@router.get("/internal/node/{node_id}/swapper", response_model=NodeSwapperDetail)
+async def get_node_swapper_detail(node_id: str):
+    """
+    Get detailed Swapper Service status for a node.
+    Used by Node Cabinet to show loaded models and health.
+    """
+    try:
+        # Fetch from node_cache
+        metrics = await repo_city.get_node_metrics(node_id)
+        if not metrics:
+            raise HTTPException(status_code=404, detail="Node not found")
+            
+        # Parse swapper state (stored as JSONB)
+        state = metrics.get("swapper_state") or {}
+        models_data = state.get("models", [])
+        
+        models = [
+            SwapperModel(
+                name=m.get("name", "unknown"),
+                loaded=m.get("loaded", False),
+                type=m.get("type"),
+                vram_gb=m.get("vram_gb")
+            )
+            for m in models_data
+        ]
+        
+        return NodeSwapperDetail(
+            node_id=node_id,
+            healthy=metrics.get("swapper_healthy", False),
+            models_loaded=metrics.get("swapper_models_loaded", 0),
+            models_total=metrics.get("swapper_models_total", 0),
+            models=models
+        )
+    except HTTPException:
+        raise
+    except Exception as e:
+        logger.error(f"Failed to get swapper detail for {node_id}: {e}")
+        return NodeSwapperDetail(
+            node_id=node_id,
+            healthy=False,
+            models_loaded=0,
+            models_total=0,
+            models=[]
+        )
+
+
 @router.get("/internal/node/{node_id}/directory-check")
 async def check_node_in_directory(node_id: str):
     """