v1.2.1

Added

• GitHub Actions: CI workflow (PHPUnit on PHP 8.3 + 8.4)
• GitHub Actions: conventional commits validation
• GitHub Actions: automated draft release on push to main
• GitHub Actions: PR validation (CHANGELOG entry check)
• GitHub Actions: stale issue/PR cleanup
• Renovate bot for dependency updates

Changed

• PR validation now requires version bump in
  composer.json and matching CHANGELOG entry.
• Release workflow reads version from composer.json
  instead of parsing CHANGELOG.md.
• Added version, authors, homepage, support,
  and keywords to composer.json.
• Track composer.lock for Renovate dependency
  management.

Fixed

• Skip merge commits in conventional commit validation.
• Remove edited PR trigger from commit validation
  to avoid redundant runs on description changes.
• README installation section now shows VCS repository
  setup (package is not yet on Packagist).
• README ImplicitPostFunction docs updated to reflect
  redesigned error codes from v1.2.0.