v0.17.4

Fixed

• Release workflow sync-main step (closes #105). The prior logic
  tried to fast-forward develop TO main's SHA, which is backwards
  for the operator's actual release flow:

  git tag vX.Y.Z develop && git push origin vX.Y.Z
  

  develop sits AHEAD of main with every commit since the previous
  release, so PATCH refs/heads/develop -f sha=MAIN_SHA -F force=false
  failed with "Update is not a fast forward" (HTTP 422) on v0.16.1,
  v0.17.0, v0.17.1, v0.17.2, and v0.17.3 in a row. The failure was
  benign — publish + GitHub Release already succeeded — but every
  release showed a red workflow on the CI dashboard.

  New logic advances main → tag SHA so main reliably tracks "last
  released SHA": resolves the pushed tag (peels annotated tags to their
  commit), no-ops if main is already there, fast-forwards main strictly
  (force=false), and exits non-zero with a clear error if the tag isn't
  a descendant of main (rare hotfix-on-main path; human reconciles).
  Removes the obsolete "develop was auto-deleted by release-PR merge"
  branch — the operator's flow doesn't run a develop→main PR, so develop
  is never auto-deleted.