feat: MCP/OpenAPI tool calling support

steward/config.py

@@ -32,6 +32,12 @@ class Settings(BaseSettings):
     # Thread memory
     thread_memory_path: str = "thread_memory.json"
 
+    # MCP / OpenAPI tool server (open-webui/openapi-servers compatible)
+    # Set MCP_SERVER_URL to enable tool calling. The service fetches
+    # /openapi.json from this URL to discover available tools.
+    mcp_server_url: str = ""
+    mcp_server_api_key: str = ""
+
 
 def get_settings() -> Settings:
     """Return application settings singleton."""