fix: remove stale palace_path reference in test helper

_patch_mcp_server had palace_path removed from its signature but the
assertion body still referenced it, causing NameError at runtime and
F821 from ruff.

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

tests/test_mcp_server.py

@@ -13,9 +13,6 @@ def _patch_mcp_server(monkeypatch, config, kg):
     """Patch the mcp_server module globals to use test fixtures."""
     from mempalace import mcp_server
 
-    assert (
-        getattr(config, "palace_path", None) == palace_path
-    ), f"config.palace_path ({getattr(config, 'palace_path', None)!r}) does not match palace_path fixture ({palace_path!r})"
     monkeypatch.setattr(mcp_server, "_config", config)
     monkeypatch.setattr(mcp_server, "_kg", kg)