Squash-only merges: the PR title is the release commit

Context and Problem Statement

Consumers install a version-keyed cache of this plugin — a whole-repo checkout of the tagged commit — so a fix to anything they run only reaches them once a release is cut here. This repo squash-merges, which makes the pull request title, not any commit on the branch, the message release-please reads on main. (Context lifted from the $comment key in release-please-config.json; #27, widened by #55.)

Considered Options

• Merge commits, and let release-please read the individual commit subjects.
• Squash merges, with the PR title gated for a releasable Conventional Commits type.
• Squash merges with no gate, relying on review to catch an unreleasable title.

Decision Outcome

main is linear and squash-only — allow_merge_commit and allow_rebase_merge are both false server-side — and scripts/release-title-gate.sh fails any PR that touches shipped plugin content without a releasable title, defining “shipped” by exclusion from a NON_SHIPPED list rather than by enumeration, with a carve-out for release-please’s own chore(main): release X.Y.Z PR so a release can still merge.

Consequences

Change the merge strategy, or that script’s releasable set, and the delivery guarantee has to be re-established somewhere else. The gate only sees the pull_request event, so two holes stay open by construction: overriding the squash subject at merge time, and a direct push to main.