[loop-cycle-30] fix: gitea-mcp binary name + test stabilization

1. gitea-mcp → gitea-mcp-server (brew binary name). Fixes Timmy's
   Gitea triage — MCP server can now be found on PATH.
2. Mark test_returns_dict_with_expected_keys as @pytest.mark.slow —
   it runs pytest recursively and always exceeds the 30s timeout.
3. Fix ruff F841 lint in test_cli.py (unused result= variable).

tests/timmy/test_cli.py

@@ -282,7 +282,7 @@ def test_repl_skips_empty_input():
         patch("timmy.session.chat") as mock_chat,
     ):
         mock_chat.return_value = "Response"
-        result = runner.invoke(app, ["repl"])
+        runner.invoke(app, ["repl"])
 
     # chat should only be called once (for "hello"), empty lines are skipped, exit breaks
     assert mock_chat.call_count == 1