The .timmy_gitea_token file in repo root was checked BEFORE config-provided
token_file, causing tests to leak real tokens and fail on any machine with
the file present.
Reorders priority: config[token] > config[token_file] > .timmy_gitea_token
Adds Path.exists monkeypatch in test_returns_none_when_no_token to isolate
from repo-root state.
Fixes 2 test failures on main.