# DEVX-179: auto-merge must never select `[skip ci]` squash titles

## Problem

PR #351 squash-merged as `DEVX-178: chore: update badge URLs to commit
4422c70b [skip ci]`. `extract_conventional_msg` picked a commit subject
carrying `[skip ci]` — a master badge commit surfaced in the PR's commit
list after force-push/amend rewrote branch history. The resulting merge
commit suppressed the post-merge push run: no release, no publish, no
wiki sync, no Vikunja close.

PR #352 shows the secondary defect: two `ci:` commits on the branch and
the older one won the tie, so the squash title described a throwaway
retrigger commit instead of the real change.

## Approach

REQ-1: Subjects containing `[skip ci]`, `[ci skip]`, or `[skip actions]`
(case-insensitive) are ineligible merge titles. They are excluded before
priority scoring, so a badge/chore/`[skip ci]` commit can never suppress
the post-merge pipeline again.

REQ-2: Equal-priority ties resolve to the newest commit in the returned
list (Gitea returns PR commits newest-first; iterate in returned order
and keep the first best candidate).

## Test Plan

- `test_auto_merge.py`: commits `[ci retrigger, badge-chore-skipci]` →
  the `ci` subject wins; commits `[older-ci, newer-ci]` → newest wins;
  all commits `[skip ci]` → falls back to newest non-skipped subject.
- `make pytest-cov` (100% gate), `make lint-all`.

## Deploy Plan

Merge as `fix:` → post-merge cuts a release that also ships DEVX-178's
PLAYBOOK_ROLE_MAP entry.

## Rollback Plan

Revert the squash commit; extract behavior returns to the previous
(unhardened) selection.

## Acceptance Criteria

- [x] REQ-1: `[skip ci]`/`[ci skip]`/`[skip actions]` subjects are never
  selected.
- [x] REQ-2: Equal-priority ties pick the newest commit.
- [x] Unit tests cover both; 100% coverage maintained.