chore: roadmap housekeeping and orientation rule

- Mark 0017, 0018 phase 1 and phase 2 HITL as complete in roadmap
- Add pre-0019 cleanup block: 0018 phase 3, write-eval refactor, eval updates
- Add orientation question rule to CONTEXT.md — read ROADMAP and open issue handoffs before answering "what's next?" questions
- Note close-out workflow gap in 0018 phase 3 grill questions

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

docs/issues/0018-factory-write-skill.md

@@ -43,6 +43,7 @@ Define the canonical documentation convention for this repo — the missing inpu
 - Global defaults vs. repo-specific overrides — what layer does the convention live at?
 - What format standards apply per type? (required headers, prose vs structured, max length)
 - Does `write-docs` need to be updated after the convention is defined, or does it reference it at runtime?
+- **Close-out workflow gap (consider in grill):** the roadmap housekeeping section drifts out of sync because there is no explicit step requiring it to be updated when work is completed. The issue acceptance checklist gets updated; the roadmap does not. Should the doc convention (or a close-out convention) define a rule for this? Or does it belong in the development workflow section of ROADMAP.md itself?
 
 **Expected outputs:**
 - `docs/notes/doc-convention.md` — the convention document (file/folder/content structure, per-type rules, override model)