v1.23.0.0 feat: always prefix PR titles with v<VERSION> (#1284)

* feat: add bin/gstack-pr-title-rewrite.sh shared helper

Single source of truth for "rewrite a PR title to start with v<VERSION>".
Three cases: already correct (no-op), different prefix (replace), no prefix
(prepend). Rejects malformed VERSION (anything outside ^[0-9]+(\.[0-9]+)*$)
with exit code 2. Uses literal case prefix match instead of bash's pattern-
matching # operator so a VERSION with glob metacharacters cannot mismatch.

Free bun test covers the four branches plus malformed-input rejection,
plain-words-not-stripped, single-segment-not-stripped, idempotence, and
missing-args. 9 tests, ~400ms.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* feat(skills): /ship and /document-release always prefix PR titles with v<VERSION>

ship/SKILL.md.tmpl Step 19: idempotency block now always rewrites titles
to start with v$NEW_VERSION via the new helper. Removes the "custom title
kept intentionally" loophole that let unprefixed titles persist forever.
Adds a post-edit self-check that re-fetches the title and retries once if
the edit didn't stick. Inline comments on the create-PR snippets at lines
867 and 876 make the rule unmissable.

document-release/SKILL.md.tmpl Step 9: new "PR/MR title sync" sub-step
calls the same helper after the body update. Catches the case where Step 8
bumped VERSION after /ship had already created the PR — title now follows
VERSION instead of going stale.

Golden fixtures regenerated for claude/codex/factory ship variants.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* feat(ci): pr-title-sync rewrites titles unconditionally

Drops the "eligible only if already prefixed" gate. Sources the new shared
helper, rewrites unconditionally on every VERSION change. Defense-in-depth
backstop for PRs opened outside the skills (manual gh pr create, web UI).

Uses env: for OLD_TITLE so YAML expression injection cannot reach run:.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

* chore: bump version and changelog (v1.23.0.0)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "1.21.1.0",
+  "version": "1.23.0.0",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",