fix: Codex filesystem boundary — prevent skill-file prompt injection (v0.12.10.0) (#570)

* fix: add filesystem boundary to all codex prompts

Codex CLI can read files outside the repo root despite -s read-only.
It discovers ~/.claude/skills/ and ~/.agents/skills/, treats SKILL.md
files as instructions, and executes preamble scripts instead of
reviewing code. Fix: prepend a boundary instruction to all 11 codex
exec/review callsites across codex/SKILL.md.tmpl (3), autoplan/
SKILL.md.tmpl (3), and scripts/resolvers/review.ts (5). Add rabbit-
hole detection rule and 5 regression tests.

* chore: bump version and changelog (v0.12.10.0)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "0.12.9.0",
+  "version": "0.12.10.0",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",