Agent Skills: accelint-qrspi-archive

Archive an OpenSpec change end-to-end. This skill invokes openspec-archive-change or openspec-bulk-archive-change itself to perform the native merge, then immediately follows up with the cross-capability linking and running indices OpenSpec doesn't build on its own — linking every capability a change touched via a shared `related:` frontmatter list, keeping `openspec/specs/INDEX.md` current, and appending a row to `openspec/changes/archive/INDEX.md`. Use this skill whenever the user wants to archive a change, says "archive this change", "bulk archive these changes", "run openspec-archive-change", "run openspec-bulk-archive-change", "update the specs index", "cross-link the specs", or wants the archived-change changelog kept current. This skill is purely additive on the linking side — it never prunes a `related:` entry and never changes a change's `Status` column after the initial write; that pruning/synthesis work belongs to `accelint-archive-synthesis`.