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>

apps/api/src/stitcher/interfaces/index.ts

@@ -0,0 +1 @@
+export * from "./job-dispatch.interface";

apps/api/src/stitcher/interfaces/job-dispatch.interface.ts

@@ -0,0 +1,39 @@
+/**
+ * Result of job dispatch operation
+ */
+export interface JobDispatchResult {
+  jobId: string;
+  queueName: string;
+  status: string;
+  estimatedStartTime?: Date;
+}
+
+/**
+ * Guard Rails result - capability permission check
+ */
+export interface GuardRailsResult {
+  allowed: boolean;
+  reason?: string;
+  requiredCapability?: string;
+}
+
+/**
+ * Quality Rails result - mandatory gate check
+ */
+export interface QualityRailsResult {
+  required: boolean;
+  gates: string[];
+  skipReason?: string;
+}
+
+/**
+ * Job dispatch context
+ */
+export interface JobDispatchContext {
+  workspaceId: string;
+  type: string;
+  priority?: number;
+  guardRails?: GuardRailsResult;
+  qualityRails?: QualityRailsResult;
+  metadata?: Record<string, unknown>;
+}