docs: Chunk 3 issues 0015-0028 and doc updates

14 issues created covering AGENTS.md refactor prerequisite, skill
implementation workflow grill, bootstrap skills (write-eval, write-skill),
remaining factory skills, and one issue per skill category group through
to chunk closure. All HITL; acceptance criteria for 0017-0028 to be
refined after 0016 grill session.

Doc updates: CONTEXT.md PRD/issue scope clarified (HOW distribution
across architecture-review and issue design notes); ROADMAP.md housekeeping
updated with bootstrap order and issue range; spec/overview.md recent
changes entry added; PRD updated (skills-index: delete → update).

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

docs/spec/overview.md

@@ -41,5 +41,6 @@ For chunk planning and open questions, see `docs/ROADMAP.md`.
 
 ## Recent changes
 
+- 2026-05-17 — Chunk 3 issues created (0015–0028): AGENTS.md refactor prerequisite, skill workflow grill, bootstrap skills (write-eval, write-skill), factory/design/implement/test/review/deploy/operate/IaC/cross-cutting skill groups, chunk closure; all HITL; acceptance criteria for 0017–0028 to be refined after issue 0016 grill session
 - 2026-05-17 — behavioral tests fully resolved: `CONTEXT.md` now always-loaded via `@import` in repo `CLAUDE.md`; standing rule added to check `docs/adr/` and ROADMAP resolved entries before answering design questions; communication/behavior and secrets rules tightened; Chunk 2 and Governance Phase 1 ✅ complete
 - 2026-05-17 — added `LESSONS.md` (issue 0013) and `docs/spec/` (issue 0014); refactored `docs/VISION.md` to goals/intent only