Add project tagging to store tool and metadata.project index

- Add explicit `project` parameter to qdrant-store tool (default: "global")
- Auto-inject project name into metadata for every stored record
- Create keyword payload index on metadata.project for efficient filtering

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/mcp_server_qdrant/qdrant.py

@@ -211,8 +211,14 @@ class QdrantConnector:
                 sparse_vectors_config=sparse_config,
             )
 
-            # Create payload indexes if configured
+            # Always index metadata.project for efficient filtering
+            await self._client.create_payload_index(
+                collection_name=collection_name,
+                field_name="metadata.project",
+                field_schema=models.PayloadSchemaType.KEYWORD,
+            )
 
+            # Create payload indexes if configured
             if self._field_indexes:
                 for field_name, field_type in self._field_indexes.items():
                     await self._client.create_payload_index(