docs: update roadmap for Phase 18

Author: Antigravity AI

ROADMAP.md

@@ -328,12 +328,12 @@
 
 ### Planned Features:
 
-- [ ] **"Why Does This Code Exist?" Narratives**: AI-generated archaeological record
+- [x] **"Why Does This Code Exist?" Narratives**: AI-generated archaeological record
 - [ ] **Onboarding Autopilot**: Personalized onboarding guides for new members
 - [ ] **3D Knowledge Graph**: Interactive Three.js-powered visualization
 - [ ] **Code DNA Profile**: Visual developer fingerprint (radial charts)
 - [ ] **Time-Travel Replay**: Animated knowledge graph evolution
-- [ ] **MCP Server**: Expose DevContext tools to AI assistants (Claude/Cursor)
+- [x] **MCP Server**: Expose DevContext tools to AI assistants (Claude/Cursor)
 - [ ] **Browser Extension**: Overlays for GitHub/GitLab
 - [ ] **Plugin System**: Extensible architecture for custom adapters