[ExtraToast]

What changed

Adds pr-title-check.yml, a reusable workflow that fails a pull request whose title or commits are not Conventional Commits, or whose body or commits credit a coding agent.

• scripts/pr_title_check.py checks the title, the body and every commit in the pull request's range. The rules are ported from deploy-kit's scripts/check-pr-title.ts: the eleven types release-please reads, an optional scope and !, and release and merge lines accepted as they are. Agent attribution covers a Co-Authored-By trailer naming an agent, a "generated with" banner naming one, and a link back to an agent session, with the same host-boundary matching.
• pr-title-check.yml checks out the pull request's head, so the range holds only its own commits. It runs the script from its own released tag, like quarantine-check.yml. The title and body reach the script through the environment, never through the shell.
• release-please-config.json keeps that tag in step, and the README lists the workflow.

Why

Every repository needs this check. Today only deploy-kit has it, as a Node script. estate-kit is the first consumer: its CI calls this workflow inside Pipeline Complete.

Tracking

None: no issue tracks this.

Verification

• tests/test_pr_title_check.py: 24 tests. CI holds the script at 100% line and branch coverage, like the other gate scripts.
• The full suite passes locally (276 tests), and actionlint is clean.
• Pipeline Complete is green
• Tracking issue updated to reflect this PR

Versioning impact

A new reusable workflow, so the next release is a minor one: 0.34.3 to 0.35.0. No existing workflow changes.