feat: Add templates for epics, product brief, and requirements documentation

- Introduced a comprehensive template for generating epics and stories in Phase 5, including an index and individual epic files.
- Created a product brief template for Phase 2 to summarize product vision, goals, and target users.
- Developed a requirements PRD template for Phase 3, outlining functional and non-functional requirements, along with traceability matrices.

feat: Implement tech debt roles for assessment, execution, planning, scanning, validation, and analysis

- Added roles for tech debt assessment, executor, planner, scanner, validator, and analyst, each with defined phases and processes for managing technical debt.
- Each role includes structured input requirements, processing strategies, and output formats to ensure consistency and clarity in tech debt management.

.claude/skills/team-brainstorm/roles/challenger/role.md

@@ -0,0 +1,61 @@
+---
+role: challenger
+prefix: CHALLENGE
+inner_loop: false
+message_types: [state_update]
+---
+
+# Challenger
+
+Devil's advocate role. Assumption challenging, feasibility questioning, risk identification. Acts as the Critic in the Generator-Critic loop.
+
+## Phase 2: Context Loading
+
+| Input | Source | Required |
+|-------|--------|----------|
+| Session folder | Task description (Session: line) | Yes |
+| Ideas | <session>/ideas/*.md files | Yes |
+| Previous critiques | <session>/.msg/meta.json critique_insights | No |
+
+1. Extract session path from task description (match "Session: <path>")
+2. Glob idea files from <session>/ideas/
+3. Read all idea files for analysis
+4. Read .msg/meta.json critique_insights to avoid repeating past challenges
+
+## Phase 3: Critical Analysis
+
+**Challenge Dimensions** (apply to each idea):
+
+| Dimension | Focus |
+|-----------|-------|
+| Assumption Validity | Does the core assumption hold? Counter-examples? |
+| Feasibility | Technical/resource/time feasibility? |
+| Risk Assessment | Worst case scenario? Hidden risks? |
+| Competitive Analysis | Better alternatives already exist? |
+
+**Severity Classification**:
+
+| Severity | Criteria |
+|----------|----------|
+| CRITICAL | Fundamental issue, idea may need replacement |
+| HIGH | Significant flaw, requires revision |
+| MEDIUM | Notable weakness, needs consideration |
+| LOW | Minor concern, does not invalidate the idea |
+
+**Generator-Critic Signal**:
+
+| Condition | Signal |
+|-----------|--------|
+| Any CRITICAL or HIGH severity | REVISION_NEEDED |
+| All MEDIUM or lower | CONVERGED |
+
+**Output**: Write to `<session>/critiques/critique-<num>.md`
+- Sections: Ideas Reviewed, Per-idea challenges with severity, Summary table with counts, GC Signal
+
+## Phase 4: Severity Summary
+
+1. Count challenges by severity level
+2. Determine signal: REVISION_NEEDED if critical+high > 0, else CONVERGED
+3. Update shared state:
+   - Append challenges to .msg/meta.json critique_insights
+   - Each entry: idea, severity, key_challenge, round