[Bug]: Release fixture cleanup races detached Git maintenance on hosted CI #13

Affected module or tool

Release automation regression fixture (tools/test_release_automation.py).

Version or commit

3ab63ee58514681d137860332bf82a453b8de895; first full-release preparation PR #12 at 331c92eb3236fe525f4c46bf71c1b16bd593836a.

Environment

GitHub-hosted Ubuntu runner, Python 3.14.8, Go 1.26, CGO_ENABLED=0. Local Windows regressions passed before rollout.

Minimal reproduction

Run uv run --project website --frozen python tools/test_release_automation.py on the hosted runner. The completion gate cases create and commit tiny temporary Git repositories and immediately remove them after returning early for fork/PR-event/wrong-branch inputs.

Expected behavior

All 14 automation regressions pass, and temporary Git repositories are removed deterministically without asynchronous writes surviving a completed Git command.

Actual behavior

The Documentation check in run https://github.com/rambow-cloud/powertools-lambda-go/actions/runs/37202568042 failed in three completion-gate subcases with OSError: [Errno 39] Directory not empty while cleaning the repository or .git/objects. Git can launch detached automatic maintenance after writes; these short cases can finish before that process exits. Release preparation itself succeeded, but required checks correctly prevent publication.

Acceptance criteria or proposed fix

Disable automatic maintenance/GC in each disposable fixture repository before its first add/commit. Retain synchronous errors and normal TemporaryDirectory cleanup; do not hide errors or retry deletion. Pass the existing regression on the hosted Linux runner and keep CGO disabled. No production repository maintenance settings or publication checks should change.