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/validator.md

@@ -0,0 +1,117 @@
+---
+prefix: VALIDATE
+inner_loop: false
+message_types:
+  success: validate_complete
+  error: error
+  fix: fix_required
+---
+
+# Architecture Validator
+
+Validate refactoring changes by running build checks, test suites, dependency metric comparisons, and API compatibility verification. Ensure refactoring improves architecture without breaking functionality.
+
+## Phase 2: Environment & Baseline Loading
+
+| Input | Source | Required |
+|-------|--------|----------|
+| Architecture baseline | <session>/artifacts/architecture-baseline.json (shared) | Yes |
+| Refactoring plan / detail | Varies by mode (see below) | Yes |
+| shared-memory.json | <session>/wisdom/shared-memory.json | Yes |
+
+1. Extract session path from task description
+2. **Detect branch/pipeline context** from task description:
+
+| Task Description Field | Value | Context |
+|----------------------|-------|---------
+| `BranchId: B{NN}` | Present | Fan-out branch -- validate only this branch's changes |
+| `PipelineId: {P}` | Present | Independent pipeline -- use pipeline-scoped baseline |
+| Neither present | - | Single mode -- full validation |
+
+3. **Load architecture baseline**:
+   - Single / Fan-out: Read `<session>/artifacts/architecture-baseline.json` (shared baseline)
+   - Independent: Read `<session>/artifacts/pipelines/{P}/architecture-baseline.json`
+
+4. **Load refactoring context**:
+   - Single: Read `<session>/artifacts/refactoring-plan.md` -- all success criteria
+   - Fan-out branch: Read `<session>/artifacts/branches/B{NN}/refactoring-detail.md` -- only this branch's criteria
+   - Independent: Read `<session>/artifacts/pipelines/{P}/refactoring-plan.md`
+
+5. Load shared-memory.json for project type and refactoring scope
+6. Detect available validation tools from project:
+
+| Signal | Validation Tool | Method |
+|--------|----------------|--------|
+| package.json + tsc | TypeScript compiler | Type-check entire project |
+| package.json + vitest/jest | Test runner | Run existing test suite |
+| package.json + eslint | Linter | Run lint checks for import/export issues |
+| Cargo.toml | Rust compiler | cargo check + cargo test |
+| go.mod | Go tools | go build + go test |
+| Makefile with test target | Custom tests | make test |
+| No tooling detected | Manual validation | File existence + import grep checks |
+
+7. Get changed files scope from shared-memory:
+   - Single: `refactorer` namespace
+   - Fan-out: `refactorer.B{NN}` namespace
+   - Independent: `refactorer.{P}` namespace
+
+## Phase 3: Validation Execution
+
+Run validations across four dimensions:
+
+**Build validation**:
+- Compile/type-check the project -- zero new errors allowed
+- Verify all moved/renamed files are correctly referenced
+- Check for missing imports or unresolved modules
+
+**Test validation**:
+- Run existing test suite -- all previously passing tests must still pass
+- Identify any tests that need updating due to module moves (update, don't skip)
+- Check for test file imports that reference old paths
+
+**Dependency metric validation**:
+- Recalculate architecture metrics post-refactoring
+- Compare coupling scores against baseline (must improve or stay neutral)
+- Verify no new circular dependencies introduced
+- Check cohesion metrics for affected modules
+
+**API compatibility validation**:
+- Verify public API signatures are preserved (exported function/class/type names)
+- Check for dangling references (imports pointing to removed/moved files)
+- Verify no new dead exports introduced by the refactoring
+- Check that re-exports maintain backward compatibility where needed
+
+**Branch-scoped validation** (fan-out mode):
+- Only validate metrics relevant to this branch's refactoring (from refactoring-detail.md)
+- Still check for regressions across all metrics (not just branch-specific ones)
+
+## Phase 4: Result Analysis
+
+Compare against baseline and plan criteria:
+
+| Metric | Threshold | Verdict |
+|--------|-----------|---------|
+| Build passes | Zero compilation errors | PASS |
+| All tests pass | No new test failures | PASS |
+| Coupling improved or neutral | No metric degradation > 5% | PASS |
+| No new cycles introduced | Cycle count <= baseline | PASS |
+| All plan success criteria met | Every criterion satisfied | PASS |
+| Partial improvement | Some metrics improved, none degraded | WARN |
+| Build fails | Compilation errors detected | FAIL -> fix_required |
+| Test failures | Previously passing tests now fail | FAIL -> fix_required |
+| New cycles introduced | Cycle count > baseline | FAIL -> fix_required |
+| Dangling references | Unresolved imports detected | FAIL -> fix_required |
+
+1. Write validation results to output path:
+   - Single: `<session>/artifacts/validation-results.json`
+   - Fan-out: `<session>/artifacts/branches/B{NN}/validation-results.json`
+   - Independent: `<session>/artifacts/pipelines/{P}/validation-results.json`
+   - Content: Per-dimension: name, baseline value, current value, improvement/regression, verdict; Overall verdict: PASS / WARN / FAIL; Failure details (if any)
+
+2. Update `<session>/wisdom/shared-memory.json` under scoped namespace:
+   - Single: merge `{ "validator": { verdict, improvements, regressions, build_pass, test_pass } }`
+   - Fan-out: merge `{ "validator.B{NN}": { verdict, improvements, regressions, build_pass, test_pass } }`
+   - Independent: merge `{ "validator.{P}": { verdict, improvements, regressions, build_pass, test_pass } }`
+
+3. If verdict is FAIL, include detailed feedback in message for FIX task creation:
+   - Which validations failed, specific errors, suggested investigation areas