PR-004A: Mission Import API — MVP-0 First Field Upload

- POST /api/v1/missions/import — multipart upload with video
- GET /api/v1/missions/:id — retrieve mission
- GET /api/v1/missions — list active missions
- Express + multer for file handling
- Uses application layer handlers (PR-002.5)
- In-memory repositories (swap for PostgreSQL in PR-003B)

Acceptance Tests (5/5 passing):
✅ Import mission with video
✅ Reject upload without video
✅ Retrieve mission by ID
✅ 404 for non-existent mission
✅ Health check

MVP-0 Definition of Done:
✅ Phone → Upload → Store → Retrieve
✅ No AI required
✅ First real artifact produced

Next: PR-005A — Minimal Mission Import UI

packages/api/.gitignore

@@ -0,0 +1,5 @@
+node_modules/
+dist/
+coverage/
+*.log
+uploads/