# Task ID: 124

**Title:** Epic service layer with revision integration

**Status:** pending

**Dependencies:** 123

**Priority:** medium

**Description:** Create EpicService with CRUD operations, revision tracking via ResourceRevision, and done-criteria roll-up logic

**Details:**

Create src/mcpd/src/services/epic.service.ts:
1. Inject EpicRepository, ResourceRevisionRepository, ProjectRepository
2. create(): validate project exists, create Epic, create initial ResourceRevision with resourceType:'epic'
3. update(): bump semver, create ResourceRevision, update currentRevisionId
4. getById(), getByName(), listByProject()
5. addTradeoff(): append to acceptedTradeoffs JSON array
6. computeStatus(): roll up EpicTask completion to determine if Epic is delivered/delivered_with_tradeoffs
7. getRoadmap(): return epictask graph with per-node completeness percentages
8. Follow PromptService pattern for revision integration

**Test Strategy:**

Unit tests: test create writes revision, test update bumps semver and writes revision, test addTradeoff appends correctly, test computeStatus logic for all EpicStatus values.