fix(nodes): Normalize Router/Swapper endpoints and fix NODE2 display

Major changes:
- Normalize get_node_endpoints to use ENV vars (ROUTER_BASE_URL, SWAPPER_BASE_URL)
- Remove node_id-based URL selection logic
- Add fallback direct API call in get_node_swapper_detail
- Fix Swapper API endpoint (/models instead of /api/v1/models)
- Add router_healthy and router_version to node_heartbeat fallback
- Add ENV vars to docker-compose for Router/Swapper URLs

Documentation:
- Add TASK_PHASE_NODE2_ROUTER_SWAPPER_FIX.md with full task description
- Add NODE2_GUARDIAN_SETUP.md with setup instructions

This fixes:
- Swapper models not showing for NODE1 and NODE2
- DAGI Router agents not showing for NODE2
- Router/Swapper showing as Down/Degraded when they're actually up

services/city-service/routes_city.py

@@ -4388,43 +4388,86 @@ 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.
-    Returns fallback data if metrics not found (instead of 404).
+    
+    First tries to get data from node_cache (populated by node-guardian).
+    If not found, attempts direct call to Swapper API as fallback.
+    Returns fallback data if both fail (instead of 404).
     """
+    import httpx
+    
     try:
-        # Fetch from node_cache
+        # First, try to fetch from node_cache (preferred - populated by node-guardian)
         metrics = await repo_city.get_node_metrics(node_id)
-        if not metrics:
-            # Return fallback instead of 404 - allows UI to show pending state
-            logger.info(f"Swapper metrics not found for {node_id}, returning fallback")
+        if metrics:
+            # Parse swapper state (stored as JSONB)
+            state = metrics.get("swapper_state") or {}
+            models_data = state.get("models", [])
+            
+            models = [
+                SwapperModel(
+                    name=m.get("name", "unknown"),
+                    # Swapper uses "status": "loaded" not "loaded": true
+                    loaded=m.get("status") == "loaded" or m.get("loaded", False),
+                    type=m.get("type"),
+                    vram_gb=m.get("size_gb") or m.get("vram_gb")
+                )
+                for m in models_data
+            ]
+            
             return NodeSwapperDetail(
                 node_id=node_id,
-                healthy=False,
-                models_loaded=0,
-                models_total=0,
-                models=[]
+                healthy=metrics.get("swapper_healthy", False),
+                models_loaded=metrics.get("swapper_models_loaded", 0),
+                models_total=metrics.get("swapper_models_total", 0),
+                models=models
             )
-            
-        # Parse swapper state (stored as JSONB)
-        state = metrics.get("swapper_state") or {}
-        models_data = state.get("models", [])
         
-        models = [
-            SwapperModel(
-                name=m.get("name", "unknown"),
-                # Swapper uses "status": "loaded" not "loaded": true
-                loaded=m.get("status") == "loaded" or m.get("loaded", False),
-                type=m.get("type"),
-                vram_gb=m.get("size_gb") or m.get("vram_gb")
-            )
-            for m in models_data
-        ]
+        # Fallback: try direct call to Swapper API
+        logger.info(f"Swapper metrics not found in cache for {node_id}, trying direct API call")
+        endpoints = await repo_city.get_node_endpoints(node_id)
+        swapper_url = endpoints.get("swapper_url")
         
+        if swapper_url:
+            try:
+                async with httpx.AsyncClient(timeout=5.0) as client:
+                    # Try to get models from Swapper (endpoint: /models, not /api/v1/models)
+                    resp = await client.get(f"{swapper_url}/models")
+                    if resp.status_code == 200:
+                        data = resp.json()
+                        models_list = data.get("models", []) if isinstance(data, dict) else data
+                        
+                        models = [
+                            SwapperModel(
+                                name=m.get("name", "unknown"),
+                                loaded=m.get("status") == "loaded" or m.get("loaded", False),
+                                type=m.get("type"),
+                                vram_gb=m.get("size_gb") or m.get("vram_gb")
+                            )
+                            for m in models_list
+                        ]
+                        
+                        loaded_count = sum(1 for m in models if m.loaded)
+                        
+                        logger.info(f"✅ Direct Swapper API call successful: {loaded_count}/{len(models)} models loaded")
+                        
+                        return NodeSwapperDetail(
+                            node_id=node_id,
+                            healthy=True,
+                            models_loaded=loaded_count,
+                            models_total=len(models),
+                            models=models
+                        )
+            except Exception as api_error:
+                logger.warning(f"Direct Swapper API call failed for {node_id} at {swapper_url}: {api_error}")
+        
+        # Final fallback: return empty state
+        logger.info(f"Swapper data unavailable for {node_id}, returning fallback")
         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
+            healthy=False,
+            models_loaded=0,
+            models_total=0,
+            models=[]
         )
     except HTTPException:
         raise