gsd-workflow-guard.js was missing the // gsd-hook-version: {{GSD_VERSION}}
header that all other hook files have. The stale hook detection in
gsd-check-update.js scans all gsd-*.js files for this header and flags
any without it as stale (hookVersion: 'unknown'). This caused a
persistent '⚠ stale hooks — run /gsd:update' warning in the statusline
even on the latest version.
Added the version header to gsd-workflow-guard.js. Running /gsd:update
will reinstall the hook with the correct version stamp.