fix(fabric): use broadcast subject for NATS capabilities discovery

NATS wildcards (node.*.capabilities.get) only work for subscriptions,
not for publish. Switch to a dedicated broadcast subject
(fabric.capabilities.discover) that all NCS instances subscribe to,
enabling proper scatter-gather discovery across nodes.

Made-with: Cursor

services/memory-service/app/vector_store.py

@@ -310,15 +310,29 @@ class VectorStore:
         
     async def get_collection_stats(self) -> Dict[str, Any]:
         """Get collection statistics"""
-        memories_info = self.client.get_collection(self.memories_collection)
-        
-        return {
-            "memories": {
-                "points_count": memories_info.points_count,
-                "vectors_count": memories_info.vectors_count,
-                "indexed_vectors_count": memories_info.indexed_vectors_count
+        try:
+            memories_info = self.client.get_collection(self.memories_collection)
+            
+            points_count = getattr(memories_info, 'points_count', 0)
+            vectors_count = getattr(memories_info, 'vectors_count', points_count)
+            indexed_vectors_count = getattr(memories_info, 'indexed_vectors_count', 0)
+            
+            return {
+                "memories": {
+                    "points_count": points_count,
+                    "vectors_count": vectors_count,
+                    "indexed_vectors_count": indexed_vectors_count
+                }
+            }
+        except Exception as e:
+            logger.error("get_collection_stats_failed", error=str(e))
+            return {
+                "memories": {
+                    "points_count": 0,
+                    "vectors_count": 0,
+                    "indexed_vectors_count": 0
+                }
             }
-        }
 
 
 # Global instance