chore(backend): update build configs and remove old services

- Makefile - update commands
- langgraph.json - update LangGraph configuration
- pyproject.toml - add new dependencies
- uv.lock - update lockfile
- Remove deprecated app/gateway/services.py

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/langgraph.json

@@ -6,7 +6,10 @@
   "graphs": {
     "lead_agent": "deerflow.agents:make_lead_agent"
   },
+  "auth": {
+    "path": "./app/plugins/auth/langgraph.py:auth"
+  },
   "checkpointer": {
-    "path": "./packages/harness/deerflow/runtime/checkpointer/async_provider.py:make_checkpointer"
+    "path": "./packages/storage/store/persistence/async_provider.py:make_checkpointer"
   }
 }