refactor: consolidate skill docs, add anti-drift tests, and apply audit fixes

DLO-13: Restructure vlm-library-workflow skill as safety contract layer.
- Rewrite SKILL.md (69 lines): safety contract, execution threshold semantics,
  six-step high-risk loop, decision rules, phase skeleton
- Delete redundant references (cli-reference, workflow, command-recipes, dev-guide)
- Add triage.md (failure mapping + preflight) and dev-map.md (module→test mapping)
- Add tests/test_docs_consistency.py: 78 parametrized tests verifying documented
  vlm commands exist in CLI registry
- Add CSV path mismatch test to test_plan_review.py (4th safety gate path)
- Delete vlm-expert.skill (Gemini package, 7 months stale) and README Gemini section

DLO-2 audit fixes: rate limiter injection, symmetric quarantine categories,
review-plan safety gates, parser improvements, planner validation.

CLI modularization: commands/ directory with one module per command group.

docs/archive/2026-pre-baseline/README.md

@@ -8,6 +8,6 @@ They are **not** maintained as current project documentation.
 - `/README.md` — user guide and workflow
 - `/CHANGELOG.md` — release and refactor history
 - `/CLAUDE.md` / `/AGENTS.md` — agent/developer guidance
-- `/plans/2026-05-21-functional-code-simplification-plan-v1.md` — code simplification plan
+- `2026-05-21-functional-code-simplification-plan-v1.md` (in this archive) — completed code simplification plan
 
 Archived on 2026-05-21 as part of the functional code trim (Phase 2).