ci: add a 're-run CI' checkbox to the PR-summary bot comment

[moul]

Answers "can the bot let us re-run CI from a checkbox?" — yes. This wires it up.

What changes

• The pr-summary bot comment now ends with a checkbox:

  • 🔄 Re-run CI (maintainers only — tick to re-run this PR's checks; it unticks itself)

• A new ci-retrigger workflow listens on issue_comment (created/edited). When the box is ticked, it:
  1. verifies the person ticking has write access (ignores everyone else),
  2. finds the PR's latest link-check and awesome-lint runs and re-runs them,
  3. unticks the box (and drops a 🚀 reaction) so it's ready for next time.

Why this design

• issue_comment runs in the base-branch context with the base token, so it works for fork PRs too (a plain pull_request job can't get write permissions from a fork).
• It never checks out or runs the PR's code — it only re-runs already-recorded workflow runs via the API, so there's no privileged-execution risk. The un-tick edit re-fires the event, but with an empty box the job's if condition no longer matches, so there's no loop.

Use case

Exactly the gnockpit situation (#96): a link was red only because the target repo was temporarily private. Once it's public, a maintainer ticks the box and CI re-runs — no new commit or manual Actions navigation needed.

[github-actions]

📋 awesome-gno PR summary

No list entries added or removed in this PR.
_{Live link check — 403/429 are shown but tolerated (some hosts block CI runners). The awesome-lint and link-check jobs are the authoritative gate.}