chore(release): 0.22.0 — pr-gatekeeper pre-push mode

pr-gatekeeper gains a second mode: reviewing a staged or unpushed diff in a
GitOps repo where a branch cannot be reconciled, recording its verdict on the
issue instead of merging. New capability, so minor.

Refs mathias/infra#470

Bump-Type: minor

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "skills",
   "description": "Mathias's engineering skills library, plus the hooks and MCP servers that make it enforceable: TDD, clean code, debugging, specs, discovery, CI, and secret hygiene.",
-  "version": "0.21.0",
+  "version": "0.22.0",
   "author": {
     "name": "Mathias",
     "url": "https://git.d-ma.be/mathias"