feat: add mac-optimizer skill (92) — Claude Code only

macOS system health toolkit with 5 audit modules (packages, environment,
security, cleanup, resources) and cleanup executor. Fixed bugs from review:
- Replace GNU timeout with perl alarm (macOS compatible)
- Remove Linux-only ps --sort flag, use portable sort
- Add JSON escaping to all audit scripts
- Remove redundant classify_size branch

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

AGENTS.md

@@ -172,6 +172,16 @@ Task(
 
 **Parallel workflows:** Set `NOTEBOOKLM_HOME` per agent to avoid context conflicts.
 
+### Mac Optimizer (92)
+
+- **Claude Code only** — no Desktop version
+- Runs read-only audit scripts that output JSON lines, then presents findings as severity-ranked tables
+- 5 audit modules: packages, environment, security, cleanup, resources
+- `doctor` mode runs all 5 sequentially and presents unified report
+- **Always ask user consent** before executing any cleanup or system changes
+- Scripts are in `custom-skills/92-mac-optimizer/scripts/`
+- Reference docs in `custom-skills/92-mac-optimizer/references/`
+
 ### Reference Curator Skills (90-99)
 
 - Use **reference-curator-pipeline** for full automated curation workflows