Add subagents for discussion, document generation, and code exploration

- Introduced Discuss Subagent for lightweight multi-perspective critique, reducing overhead from ~60-90s to ~5s.
- Added Doc Generation Subagent for generating documents with CLI analysis and template filling.
- Implemented Explore Subagent for centralized codebase exploration with caching, replacing the standalone explorer role.
- Created templates for architecture documents, epics, product briefs, and requirements PRD to standardize outputs.
- Added a review file for tracking changes and discussions.

.claude/skills/team-lifecycle/role-specs/reviewer.md

@@ -0,0 +1,94 @@
+---
+role: reviewer
+prefix: REVIEW
+additional_prefixes: [QUALITY, IMPROVE]
+inner_loop: false
+discuss_rounds: [DISCUSS-006]
+subagents: [discuss]
+message_types:
+  success_review: review_result
+  success_quality: quality_result
+  fix: fix_required
+  error: error
+---
+
+# Reviewer — Phase 2-4
+
+## Phase 2: Mode Detection
+
+| Task Prefix | Mode | Dimensions | Inline Discuss |
+|-------------|------|-----------|---------------|
+| REVIEW-* | Code Review | quality, security, architecture, requirements | None |
+| QUALITY-* | Spec Quality | completeness, consistency, traceability, depth, coverage | DISCUSS-006 |
+| IMPROVE-* | Spec Quality (recheck) | Same as QUALITY | DISCUSS-006 |
+
+## Phase 3: Review Execution
+
+### Code Review (REVIEW-*)
+
+**Inputs**: Plan file, git diff, modified files, test results (if available)
+
+**4 dimensions**:
+
+| Dimension | Critical Issues |
+|-----------|----------------|
+| Quality | Empty catch, any in public APIs, @ts-ignore, console.log |
+| Security | Hardcoded secrets, SQL injection, eval/exec, innerHTML |
+| Architecture | Circular deps, parent imports >2 levels, files >500 lines |
+| Requirements | Missing core functionality, incomplete acceptance criteria |
+
+### Spec Quality (QUALITY-* / IMPROVE-*)
+
+**Inputs**: All spec docs in session folder, quality gate config
+
+**5 dimensions**:
+
+| Dimension | Weight | Focus |
+|-----------|--------|-------|
+| Completeness | 25% | All sections present with substance |
+| Consistency | 20% | Terminology, format, references |
+| Traceability | 25% | Goals -> Reqs -> Arch -> Stories chain |
+| Depth | 20% | AC testable, ADRs justified, stories estimable |
+| Coverage | 10% | Original requirements mapped |
+
+**Quality gate**:
+
+| Gate | Criteria |
+|------|----------|
+| PASS | Score >= 80% AND coverage >= 70% |
+| REVIEW | Score 60-79% OR coverage 50-69% |
+| FAIL | Score < 60% OR coverage < 50% |
+
+**Artifacts**: readiness-report.md + spec-summary.md
+
+## Phase 4: Verdict + Inline Discuss
+
+### Code Review Verdict
+
+| Verdict | Criteria |
+|---------|----------|
+| BLOCK | Critical issues present |
+| CONDITIONAL | High/medium only |
+| APPROVE | Low or none |
+
+### Spec Quality Inline Discuss (DISCUSS-006)
+
+After generating readiness-report.md, call discuss subagent:
+- Artifact: `<session-folder>/spec/readiness-report.md`
+- Round: DISCUSS-006
+- Perspectives: product, technical, quality, risk, coverage (all 5)
+
+Handle discuss verdict per team-worker consensus handling protocol.
+
+> **Note**: DISCUSS-006 HIGH always triggers user pause (final sign-off gate), regardless of revision count.
+
+**Report**: mode, verdict/gate, dimension scores, discuss verdict (QUALITY only), output paths.
+
+## Error Handling
+
+| Scenario | Resolution |
+|----------|------------|
+| Missing context | Request from coordinator |
+| Invalid mode | Abort with error |
+| Analysis failure | Retry, then fallback template |
+| Discuss subagent fails | Proceed without final discuss, log warning |