chore: PR title lint + release-drafter

[constk]

Problem

Conventional commit titles drive release-drafter categorisation. If title-lint and the drafter share no source of truth for allowed prefixes, drafted release notes are wrong.

Proposed solution

Port .github/workflows/pr-title.yml enforcing the 7-prefix schema (feat/fix/docs/test/refactor/chore/release). Port .github/release-drafter.yml with categories mirroring the schema and a version-resolver. Wire .github/workflows/release-drafter.yml to update the draft release on main push and PR label/open/reopen/synchronize events.

Acceptance criteria

• PR with title wip: ... fails the lint job.
• Merging a feat: ... PR adds a line under "Features" in the draft release.
• Merging a fix: ... PR adds a line under "Bug Fixes".
• Version-resolver bumps minor on feat, patch on fix.

Priority rationale

High: release notes are part of the portfolio surface; they need to be drafted automatically and correctly.

Depends on

#2

[constk]

Both halves landed: pr-title.yml in #10's bundle (when meta-gates needed it as input); release-drafter workflow + .github/release-drafter.yml in #52.