chore: simplify actions-maintenance wrapper triggers and job name

[krukonshedul]

Summary

• Drop the explicit pull_request: types: list — it duplicated GitHub's own default (opened, synchronize, reopened), so removing it changes nothing at runtime.
• Rename the wrapper's job id from actions-maintenance to phase (displayed as Phase), so check names read Actions Maintenance / Phase / <role> instead of the redundant actions-maintenance / actions-maintenance / <role>.
• If this repo has a push trigger on the wrapper, align its presence with whether this repo is a Source in actions-manifest.yaml (owns a registered internal action) — added where missing, removed where present but not warranted.

Part of an org-wide cleanup of the actions-maintenance.yaml wrapper across ~355 repos.

• Also synced trailing # vX version comments on uses: pins with the manifest's source_ref where they'd drifted from a prior SHA-only bump (SHA itself was already correct; comment-only follow-up commit)

Test plan

• actionlint passes on the changed workflow file
• Diff reviewed for correctness against the reusable workflow's expected inputs

🤖 Generated with Claude Code

[dyl-sv]

Automated review: change is limited to the actions-maintenance workflow rename/trigger cleanup and/or SHA-pinned comment corrections (verified no dependency SHAs changed). Approving.