feat(#166): Implement Stitcher module structure

Created the mosaic-stitcher module - the workflow orchestration layer
that wraps OpenClaw.

Responsibilities:
- Receive webhooks from @mosaic bot
- Apply Guard Rails (capability permissions)
- Apply Quality Rails (mandatory gates)
- Track all job steps and events
- Dispatch work to OpenClaw with constraints

Implementation:
- StitcherModule: Module definition with PrismaModule and BullMqModule
- StitcherService: Core orchestration logic
  - handleWebhook(): Process webhooks from @mosaic bot
  - dispatchJob(): Create RunnerJob and dispatch to BullMQ queue
  - applyGuardRails(): Check capability permissions for agent profiles
  - applyQualityRails(): Determine mandatory gates for job types
  - trackJobEvent(): Log events to database for audit trail
- StitcherController: HTTP endpoints
  - POST /stitcher/webhook: Webhook receiver
  - POST /stitcher/dispatch: Manual job dispatch
- DTOs and interfaces for type safety

TDD Process:
1. RED: Created failing tests (12 tests)
2. GREEN: Implemented minimal code to pass tests
3. REFACTOR: Fixed TypeScript strict mode issues

Quality Gates: ALL PASS
- Typecheck: PASS
- Lint: PASS
- Build: PASS
- Tests: PASS (12/12)

Token estimate: ~56,000 tokens

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/scratchpads/166-stitcher-module.md

@@ -0,0 +1,101 @@
+# Issue #166: Stitcher Module Structure
+
+## Objective
+
+Create the mosaic-stitcher module - the workflow orchestration layer that wraps OpenClaw.
+
+## Prerequisites
+
+- #165 (BullMQ module) complete - BullMqService available
+- #164 (Database schema) complete - RunnerJob, JobStep, JobEvent models available
+
+## Responsibilities
+
+- Receive webhooks from @mosaic bot
+- Apply Guard Rails (capability permissions)
+- Apply Quality Rails (mandatory gates)
+- Track all job steps and events
+- Dispatch work to OpenClaw with constraints
+
+## Approach
+
+1. Examine existing module patterns (tasks, events, brain)
+2. RED: Write failing tests for StitcherService and StitcherController
+3. GREEN: Implement minimal code to pass tests
+4. REFACTOR: Clean up and improve code quality
+5. Verify quality gates pass
+
+## Progress
+
+- [x] Create scratchpad
+- [x] Examine existing module patterns
+- [x] Create directory structure
+- [x] RED: Write StitcherService tests
+- [x] RED: Write StitcherController tests
+- [x] GREEN: Implement StitcherService
+- [x] GREEN: Implement StitcherController
+- [x] Create DTOs and interfaces
+- [x] Create StitcherModule
+- [x] Register in AppModule
+- [x] REFACTOR: Improve code quality
+- [x] Run quality gates (typecheck, lint, build, test)
+- [ ] Commit changes
+
+## Quality Gates Results
+
+- **Typecheck**: PASS
+- **Lint**: PASS
+- **Build**: PASS
+- **Tests**: PASS (12 tests passing)
+
+## Patterns Observed
+
+- BullMqService is @Global() and provides queue management
+- Controllers use @UseGuards(AuthGuard, WorkspaceGuard, PermissionGuard)
+- DTOs use class-validator decorators
+- Services inject PrismaService for database operations
+- Modules follow: imports, controllers, providers, exports structure
+- Tests use Jest with describe/it blocks
+
+## Testing
+
+- Unit tests for StitcherService
+- Unit tests for StitcherController
+- Integration test for webhook endpoint
+
+## Implementation Details
+
+### Files Created
+
+1. `apps/api/src/stitcher/stitcher.module.ts` - Module definition
+2. `apps/api/src/stitcher/stitcher.service.ts` - Core orchestration service
+3. `apps/api/src/stitcher/stitcher.controller.ts` - Webhook and dispatch endpoints
+4. `apps/api/src/stitcher/dto/webhook.dto.ts` - Request/response DTOs
+5. `apps/api/src/stitcher/dto/index.ts` - DTO barrel export
+6. `apps/api/src/stitcher/interfaces/job-dispatch.interface.ts` - Job dispatch interfaces
+7. `apps/api/src/stitcher/interfaces/index.ts` - Interface barrel export
+8. `apps/api/src/stitcher/index.ts` - Module barrel export
+9. `apps/api/src/stitcher/stitcher.service.spec.ts` - Service unit tests
+10. `apps/api/src/stitcher/stitcher.controller.spec.ts` - Controller unit tests
+
+### Key Features Implemented
+
+- **Webhook endpoint**: POST /stitcher/webhook - Receives webhooks from @mosaic bot
+- **Job dispatch**: POST /stitcher/dispatch - Manual job dispatch
+- **Guard Rails**: applyGuardRails() - Capability permission checks
+- **Quality Rails**: applyQualityRails() - Mandatory gate determination
+- **Event tracking**: trackJobEvent() - Audit log for all job events
+
+### TDD Process
+
+1. **RED**: Created failing tests for service and controller
+2. **GREEN**: Implemented minimal code to pass tests
+3. **REFACTOR**: Fixed TypeScript strict mode issues with exactOptionalPropertyTypes
+
+### Integration
+
+- Registered StitcherModule in AppModule
+- Imports PrismaModule and BullMqModule
+- Exports StitcherService for use in other modules
+
+## Notes