feat(gates): enforce metadata.version bumps on changed skills at pre-push

check-skill-version-bump fails a push when a skill directory changed
against its merge-base with main (tests/ excluded) without a strictly
higher metadata.version than main. New, renamed and deleted skills are
exempt; every plugin is covered. Recorded as a dated section in
ADR-0022 and documented in gates.md.

Patch-bumps the 17 skills that changed on this branch without a bump,
so the branch passes its own gate. Simplification audit finding 33.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

plugins/core/.apm/skills/agentsmd-audit/SKILL.md

@@ -14,7 +14,7 @@ metadata:
     - context7-websites-agents-md
     - context7-agentsmd-agents-md
     - governance-secrets-hard-prohibition
-  version: "0.1.2"
+  version: "0.1.3"
 ---
 
 ## Gotchas

plugins/core/.apm/skills/agentsmd-author/SKILL.md

@@ -12,7 +12,7 @@ metadata:
     - agents-md-official
     - context7-websites-agents-md
     - context7-agentsmd-agents-md
-  version: "0.1.2"
+  version: "0.1.3"
 ---
 
 ## Gotchas

plugins/core/.apm/skills/provider-adapter-author/SKILL.md

@@ -11,7 +11,7 @@ metadata:
   category: docs
   source_keys:
     - adr-0002-0003-two-tier-claude-md
-  version: "0.1.1"
+  version: "0.1.2"
 ---
 
 ## Gotchas