feat(skill): add team-arch-opt architecture optimization skill

New team skill focused on structural architecture improvements
(dependency cycles, coupling/cohesion, layering violations, God Classes,
dead code). Isomorphic to team-perf-opt with pipeline:
ANALYZE → DESIGN → REFACTOR → VALIDATE + REVIEW.

Roles: coordinator, analyzer, designer, refactorer, validator, reviewer.
Supports single/fan-out/independent/auto parallel modes.

.claude/skills/team-arch-opt/role-specs/designer.md

@@ -0,0 +1,118 @@
+---
+prefix: DESIGN
+inner_loop: false
+discuss_rounds: [DISCUSS-REFACTOR]
+subagents: [discuss]
+message_types:
+  success: design_complete
+  error: error
+---
+
+# Refactoring Designer
+
+Analyze architecture reports and baseline metrics to design a prioritized refactoring plan with concrete strategies, expected structural improvements, and risk assessments.
+
+## Phase 2: Analysis Loading
+
+| Input | Source | Required |
+|-------|--------|----------|
+| Architecture report | <session>/artifacts/architecture-report.md | Yes |
+| Architecture baseline | <session>/artifacts/architecture-baseline.json | Yes |
+| shared-memory.json | <session>/wisdom/shared-memory.json | Yes |
+| Wisdom files | <session>/wisdom/patterns.md | No |
+
+1. Extract session path from task description
+2. Read architecture report -- extract ranked issue list with severities and categories
+3. Read architecture baseline -- extract current structural metrics
+4. Load shared-memory.json for analyzer findings (project_type, scope)
+5. Assess overall refactoring complexity:
+
+| Issue Count | Severity Mix | Complexity |
+|-------------|-------------|------------|
+| 1-2 | All Medium | Low |
+| 2-3 | Mix of High/Medium | Medium |
+| 3+ or any Critical | Any Critical present | High |
+
+## Phase 3: Strategy Formulation
+
+For each architecture issue, select refactoring approach by type:
+
+| Issue Type | Strategies | Risk Level |
+|------------|-----------|------------|
+| Circular dependency | Interface extraction, dependency inversion, mediator pattern | High |
+| God Class/Module | SRP decomposition, extract class/module, delegate pattern | High |
+| Layering violation | Move to correct layer, introduce Facade, add anti-corruption layer | Medium |
+| Code duplication | Extract shared utility/base class, template method pattern | Low |
+| High coupling | Introduce interface/abstraction, dependency injection, event-driven | Medium |
+| API bloat / dead exports | Privatize internals, re-export only public API, barrel file cleanup | Low |
+| Dead code | Safe removal with reference verification | Low |
+| Missing abstraction | Extract interface/type, introduce strategy/factory pattern | Medium |
+
+Prioritize refactorings by impact/effort ratio:
+
+| Priority | Criteria |
+|----------|----------|
+| P0 (Critical) | High impact + Low effort -- quick wins (dead code removal, simple moves) |
+| P1 (High) | High impact + Medium effort (cycle breaking, layer fixes) |
+| P2 (Medium) | Medium impact + Low effort (duplication extraction) |
+| P3 (Low) | Low impact or High effort -- defer (large God Class decomposition) |
+
+If complexity is High, invoke `discuss` subagent (DISCUSS-REFACTOR round) to evaluate trade-offs between competing strategies before finalizing the plan.
+
+Define measurable success criteria per refactoring (target metric improvement or structural change).
+
+## Phase 4: Plan Output
+
+1. Write refactoring plan to `<session>/artifacts/refactoring-plan.md`:
+
+   Each refactoring MUST have a unique REFACTOR-ID and self-contained detail block:
+
+   ```markdown
+   ### REFACTOR-001: <title>
+   - Priority: P0
+   - Target issue: <issue from report>
+   - Issue type: <CYCLE|COUPLING|GOD_CLASS|DUPLICATION|LAYER_VIOLATION|DEAD_CODE|API_BLOAT>
+   - Target files: <file-list>
+   - Strategy: <selected approach>
+   - Expected improvement: <metric> by <description>
+   - Risk level: <Low/Medium/High>
+   - Success criteria: <specific structural change to verify>
+   - Implementation guidance:
+     1. <step 1>
+     2. <step 2>
+     3. <step 3>
+
+   ### REFACTOR-002: <title>
+   ...
+   ```
+
+   Requirements:
+   - Each REFACTOR-ID is sequentially numbered (REFACTOR-001, REFACTOR-002, ...)
+   - Each refactoring must be **non-overlapping** in target files (no two REFACTOR-IDs modify the same file unless explicitly noted with conflict resolution)
+   - Implementation guidance must be self-contained -- a branch refactorer should be able to work from a single REFACTOR block without reading others
+
+2. Update `<session>/wisdom/shared-memory.json` under `designer` namespace:
+   - Read existing -> merge -> write back:
+   ```json
+   {
+     "designer": {
+       "complexity": "<Low|Medium|High>",
+       "refactoring_count": 4,
+       "priorities": ["P0", "P0", "P1", "P2"],
+       "discuss_used": false,
+       "refactorings": [
+         {
+           "id": "REFACTOR-001",
+           "title": "<title>",
+           "issue_type": "<CYCLE|COUPLING|...>",
+           "priority": "P0",
+           "target_files": ["src/a.ts", "src/b.ts"],
+           "expected_improvement": "<metric> by <description>",
+           "success_criteria": "<threshold>"
+         }
+       ]
+     }
+   }
+   ```
+
+3. If DISCUSS-REFACTOR was triggered, record discussion summary in `<session>/discussions/DISCUSS-REFACTOR.md`