Fix MCP close tool method signature error (GH #107)

Renamed BdDaemonClient.close() cleanup method to cleanup() to eliminate
method name collision with async close(params) method for closing issues.

Root cause: Python method resolution meant the non-async close(self)
cleanup method was shadowing the async close(self, params) method that
closes issues, causing 'takes 1 positional argument but 2 were given'.

Changes:
- bd_daemon_client.py: Renamed close() -> cleanup()
- server.py: Updated cleanup code to call cleanup() instead of close()
- test_lifecycle.py: Updated tests to use cleanup()

All close-related tests pass. Fixes GitHub issue #107.
Tracked in bd-67 (closed).

integrations/beads-mcp/src/beads_mcp/bd_daemon_client.py

@@ -431,7 +431,7 @@ class BdDaemonClient(BdClientBase):
         except (DaemonNotRunningError, DaemonConnectionError, DaemonError):
             return False
 
-    def close(self) -> None:
+    def cleanup(self) -> None:
         """Close daemon client connections and cleanup resources.
         
         This is called during MCP server shutdown to ensure clean termination.