Tone down review loops: single-pass plan review, raise issue bar

- Remove chunk-based plan review in favor of single whole-plan review
- Add Calibration sections to both reviewer prompts so only serious
  issues block approval
- Reduce max review iterations from 5 to 3
- Streamline reviewer checklists (spec: 7→5, plan: 7→4 categories)

skills/brainstorming/SKILL.md

@@ -27,7 +27,7 @@ You MUST create a task for each of these items and complete them in order:
 4. **Propose 2-3 approaches** — with trade-offs and your recommendation
 5. **Present design** — in sections scaled to their complexity, get user approval after each section
 6. **Write design doc** — save to `docs/superpowers/specs/YYYY-MM-DD-<topic>-design.md` and commit
-7. **Spec review loop** — dispatch spec-document-reviewer subagent with precisely crafted review context (never your session history); fix issues and re-dispatch until approved (max 5 iterations, then surface to human)
+7. **Spec review loop** — dispatch spec-document-reviewer subagent with precisely crafted review context (never your session history); fix issues and re-dispatch until approved (max 3 iterations, then surface to human)
 8. **User reviews written spec** — ask user to review the spec file before proceeding
 9. **Transition to implementation** — invoke writing-plans skill to create implementation plan
 
@@ -121,7 +121,7 @@ After writing the spec document:
 
 1. Dispatch spec-document-reviewer subagent (see spec-document-reviewer-prompt.md)
 2. If Issues Found: fix, re-dispatch, repeat until Approved
-3. If loop exceeds 5 iterations, surface to human for guidance
+3. If loop exceeds 3 iterations, surface to human for guidance
 
 **User Review Gate:**
 After the spec review loop passes, ask the user to review the written spec before proceeding: