chore: protect main and the release tags - #3

main had no protection at all — a force-push or an accidental delete would
have destroyed history on a repo that is now public and published.

Three rulesets, split deliberately rather than bundled into one:

  main: no force-push, no deletion    no bypass, not even the owner
  main: PR + green checks             bypass: repository admin
  release tags are immutable          no bypass, v* cannot move or be deleted

The split is the point. Rewriting main is the only mistake here that destroys
work rather than just making a mess, so it has no escape hatch. The PR rule
does, because a solo maintainer cannot approve their own pull request and a
hard gate would mean self-blocking or fake reviews — remove the bypass actor
when there is a second maintainer.

Tags are immutable because a published npm version is. v0.5.0 must keep
pointing at the commit whose provenance attestation says it built resilix@0.5.0.

Two checks are deliberately NOT required: Deploy to Pages and release are
push-triggered only, so they never report on a pull request, and requiring a
check that cannot run blocks every merge forever.

Every rule was tested rather than assumed, which caught a bad test of my own:
`git push --force` of a descendant commit is a fast-forward, not a force, so
it proved nothing and pushed an empty commit to main. The real test is a
rewind — `push --force origin/main~1:main` — which is correctly rejected.
Deletion of main and of v0.5.0 are both rejected too.

Also closes the stale Version Packages PR. It was built from the four
changesets consumed manually during the 0.5.0 release, so it had gone
conflicting and would have rolled package.json back to 0.2.0.