[chore] Enforce mandatory technical-writer invocation in developer agent

## Summary The `developer` agent does not always invoke `technical-writer` before converting a PR from Draft to Ready for Review, despite this being a mandatory gate (Rule 10 in `developer.agent.md` and Completion Gate item 6). This issue proposes six targeted improvements to structurally enforce the invocation. ## Root Cause Analysis 1. **Weak trigger language (Rule 10 vs Rule 18):** Rule 18 (verifier) uses "with no path that skips the call" reinforcement, while Rule 10 (technical-writer) reads as a sequencing constraint only. 2. **No execution-evidence field in closeout payload:** The payload has `verifier_audit: run | blocked` but no equivalent `technical_writer_run: run | blocked` field. Agents can self-report `docs_drift_status: clean` without ever running the check. 3. **No explicit planner merge gate for technical-writer execution:** Planner verifies `verifier_audit: run` as a merge gate, but has no parallel check for technical-writer invocation evidence. 4. **Positioning at end of long completion sequence:** After quality gates and verifier audit, the "feels done" heuristic causes the agent to skip directly to PR conversion. 5. **Weaker phrasing in `implement.instructions.md`:** Uses "validation MUST include" (output quality) vs "MUST have run" (execution evidence). 6. **Missing from summary table:** The "GitHub Execution Rules Summary" table in `implement.instructions.md` doesn't list `technical-writer` as a named gate. ## Proposed Changes ### 1. Strengthen Rule 10 language in `developer.agent.md` Add "with no path that skips the call. This is not optional and is not gated behind user request" — mirroring Rule 18's language. ### 2. Add `technical_writer_run` field to closeout payload Add a binary `technical_writer_run: run | blocked` field to the closeout payload schema in both `developer.agent.md` and `planner.agent.md`. ### 3. Add planner merge gate for technical-writer execution In `planner.agent.md` Phase 4 merge management rules, add: "Verify `technical_writer_run: run` — confirms developer invoked the mandatory technical-writer pass." ### 4. Reorder execution flow: move technical-writer before verifier audit In `developer.agent.md` step 7 and `implement.instructions.md`, swap the order so docs are updated before the verifier runs. This reduces the "feels done after verifier" drop-off and ensures docs are current when the audit inspects them. ### 5. Make technical-writer a distinct numbered step in Execution Flow Instead of a bullet among many in step 7, make it an explicit numbered step (e.g., step 8) so it's visually distinct and harder to skip. ### 6. Add technical-writer to the "GitHub Execution Rules Summary" table In `implement.instructions.md`, add `technical-writer` as a named gate in the "Before closing" row of the summary table. ## Acceptance Criteria - [ ] Rule 10 in `developer.agent.md` (both `.github/agents/` and `.kiro/agents/`) uses "no path that skips the call" reinforcement language - [ ] Closeout payload schema includes `technical_writer_run: run | blocked` in `developer.agent.md` and `planner.agent.md` (all platform variants) - [ ] Planner merge gate explicitly checks `technical_writer_run: run` before merging story PRs - [ ] Execution Flow in `developer.agent.md` places technical-writer invocation before verifier audit - [ ] Technical-writer invocation is a distinct numbered step (not a sub-bullet of step 7) - [ ] `implement.instructions.md` summary table includes technical-writer as a named gate - [ ] All changes are mirrored across `.github/agents/`, `.kiro/agents/`, and `.claude/agents/` variants ## Affected Files - `.github/agents/developer.agent.md` - `.github/agents/planner.agent.md` - `.github/instructions/implement.instructions.md` - `.kiro/agents/developer.md` - `.kiro/agents/planner.md` (if exists) - `.kiro/steering/implement.md` (if exists) - `.claude/agents/developer.md` (if exists) - `.claude/agents/planner.md` (if exists) ## Non-Goals - Changing `technical-writer` agent behavior or output format - Modifying the drift/stale-doc validation logic itself - Changing the verifier audit flow