Align PR commit subjects with commitlint conventions

[Copilot]

This PR addresses the failing commitlint check on PR #247. The branch history included two commit subjects that did not follow the repository’s conventional-commit format.

• What changed

  • Reword the workflow cleanup commit to use a ci: subject
  • Reword the supporting cleanup commit to use a chore: subject

• Updated commit subjects

  • Apply workflow security fixes → chore: update workflow cleanup references
  • Remove obsolete issue manager workflow → ci: remove obsolete issue manager workflow

• Impact

  • Restores compatibility with the repository’s commitlint rules
  • Leaves the code diff unchanged; only commit metadata is updated