feat(#175): Implement E2E test harness

- Create comprehensive E2E test suite for job orchestration
- Add test fixtures for Discord, BullMQ, and Prisma mocks
- Implement 9 end-to-end test scenarios covering:
  * Happy path: webhook → job → step execution → completion
  * Event emission throughout job lifecycle
  * Step failure and retry handling
  * Job failure after max retries
  * Discord command parsing and job creation
  * WebSocket status updates integration
  * Job cancellation workflow
  * Job retry mechanism
  * Progress percentage tracking

- Add helper methods to services for simplified testing:
  * JobStepsService: start(), complete(), fail(), findByJob()
  * RunnerJobsService: updateStatus(), updateProgress()
  * JobEventsService: findByJob()

- Configure vitest.e2e.config.ts for E2E test execution
- All 9 E2E tests passing
- All 1405 unit tests passing
- Quality gates: typecheck, lint, build all passing

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

docs/scratchpads/175-e2e-harness.md

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+# Issue #175: E2E Test Harness
+
+## Objective
+
+Create a comprehensive end-to-end test harness that validates the complete flow from webhook to job completion, including chat integration.
+
+## Approach
+
+1. Explore existing test patterns in the codebase
+2. Set up E2E test directory structure
+3. Create test fixtures (Mock Discord, BullMQ, Prisma)
+4. Implement E2E test scenarios following TDD
+5. Verify all quality gates pass
+
+## Progress
+
+- [x] Create scratchpad
+- [x] Pull latest code (skipped - unstaged changes)
+- [x] Explore existing test patterns
+- [x] Create E2E directory structure
+- [x] Create vitest.e2e.config.ts
+- [x] Implement test fixtures
+  - [x] Mock Discord client fixture
+  - [x] Mock BullMQ queues fixture
+  - [x] Mock Prisma client fixture
+- [x] Write E2E tests (TDD)
+  - [x] Happy path: webhook → job → completion
+  - [x] Error handling: step failure → retry
+  - [x] Chat integration: command → job → updates
+- [x] Add helper methods to services
+  - [x] JobStepsService: start(), complete(), fail(), findByJob()
+  - [x] RunnerJobsService: updateStatus(), updateProgress()
+  - [x] JobEventsService: findByJob()
+- [x] Run quality gates
+  - [x] All 9 E2E tests passing
+  - [x] All 1405 unit tests passing
+  - [x] Typecheck passing
+  - [x] Lint passing
+  - [x] Build passing
+- [x] Commit changes
+
+## Test Patterns Observed
+
+- Use Vitest with NestJS Testing module
+- Mock services with vi.fn()
+- Use Test.createTestingModule for DI
+- Follow existing integration test pattern from quality-orchestrator
+- Mock child_process.exec for command execution
+- Create helper functions for test data
+
+## Testing
+
+### Test Scenarios
+
+1. **Happy Path**: webhook → job creation → step execution → completion
+2. **Error Handling**: step failure → retry → final failure
+3. **Chat Integration**: command → job → status updates
+
+### Quality Gates
+
+- pnpm typecheck
+- pnpm lint
+- pnpm test
+- pnpm build
+
+## Notes
+
+- All dependencies (Phase 1-4) are complete
+- Herald (#172) may complete during this task
+- Follow TDD: RED → GREEN → REFACTOR
+- Use existing test patterns as reference
+
+## Implementation Summary
+
+### Files Created
+
+1. `apps/api/vitest.e2e.config.ts` - E2E test configuration
+2. `apps/api/test/fixtures/` - Mock fixtures directory
+   - `mock-discord.fixture.ts` - Mock Discord client and messages
+   - `mock-bullmq.fixture.ts` - Mock BullMQ queues and jobs
+   - `mock-prisma.fixture.ts` - Mock Prisma service with CRUD operations
+   - `index.ts` - Fixture exports
+3. `apps/api/test/e2e/job-orchestration.e2e-spec.ts` - 9 E2E tests
+
+### Files Modified
+
+1. `apps/api/src/job-steps/job-steps.service.ts`
+   - Added `start(id)` - simplified start without jobId parameter
+   - Added `complete(id, data)` - simplified complete with optional output/tokens
+   - Added `fail(id, data)` - simplified fail with optional error message
+   - Added `findByJob(jobId)` - alias for findAllByJob
+
+2. `apps/api/src/runner-jobs/runner-jobs.service.ts`
+   - Added `updateStatus(id, workspaceId, status, data)` - update job status with timestamps
+   - Added `updateProgress(id, workspaceId, progressPercent)` - update job progress
+
+3. `apps/api/src/job-events/job-events.service.ts`
+   - Added `findByJob(jobId)` - get all events for a job without pagination
+
+### E2E Tests Coverage
+
+1. Happy path: webhook → job creation → step execution → completion
+2. Event emission throughout job lifecycle
+3. Step failure and retry handling
+4. Job failure after max retries
+5. Discord command parsing and job creation
+6. WebSocket status updates
+7. Job cancellation
+8. Job retry mechanism
+9. Progress percentage tracking