fix(ci): make the content-sync gate fire on the cases it exists to catch

`check-plugin-content-sync` was the only local pre-push hook scoped with `files:`
instead of `always_run`, and its regex missed both compiled `plugin.json` paths —
exactly the manifests the script had been taught to diff. A commit tampering only
with one of those passed the entire pre-push suite at exit 0.

A regex fix alone could not close it: pre-commit drops deleted paths from the file
list, so removing a mirror directory skipped the hook too. The `hooks\.json`
alternative was also already dead, matching only the pre-move flat path. Dropping
`files:` for `always_run: true` closes all three and makes the hook uniform with its
three siblings; the check costs ~2-4s.

Also excludes `.github/plugin/marketplace.json` from `pretty-format-json`. This was
not hypothetical: `json.dumps(indent=2, sort_keys=True)` reproduces the manifests
committed at HEAD byte-for-byte, so `--autofix` had already rewritten compiled apm
output once. Without the exclusion it would do so again on the next commit,
silently breaking the byte-identical mirror invariant.

Landing first, ahead of the regenerated manifests, so that cannot happen.

Refs: #90

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01X7GvKuJfy2WrdBmUttV4DT

.pre-commit-config.yaml

@@ -28,7 +28,7 @@ repos:
       - id: pretty-format-json
         stages: ['pre-commit']
         args: [--autofix]
-        exclude: '(^|/)(\.claude-plugin/plugin\.json|\.github/plugin/plugin\.json|\.claude-plugin/marketplace\.json)$|^\.agents/plugins/marketplace\.json$'
+        exclude: '(^|/)(\.claude-plugin/plugin\.json|\.github/plugin/plugin\.json|\.claude-plugin/marketplace\.json|\.github/plugin/marketplace\.json)$|^\.agents/plugins/marketplace\.json$'
       - id: check-yaml
         stages: ['pre-commit']
       - id: trailing-whitespace
@@ -64,12 +64,12 @@ repos:
 
       - id: check-plugin-content-sync
         name: Check plugin content sync
-        description: Verify each plugin's flat skills/agents/commands/hooks.json mirror is in sync with .apm/ -- Claude Code has no .apm/ awareness so this compiled mirror must stay current (see issue #90)
+        description: Verify each plugin's flat skills/agents/commands/hooks/hooks.json mirror is in sync with .apm/ -- Claude Code has no .apm/ awareness so this compiled mirror must stay current (see issue #90)
         entry: bash scripts/sync-plugin-content.sh --check --all
         language: system
         stages: [pre-push]
         pass_filenames: false
-        files: '^(scripts/sync-plugin-content\.sh|\.claude-plugin/marketplace\.json|plugins/[^/]+/(apm\.yml|\.mcp\.json|hooks\.json|\.apm/|agents/|skills/|commands/|instructions/|extensions/))'
+        always_run: true
 
       - id: check-marketplace-mirror-sync
         name: Check marketplace mirror sync