디테일샷 / Detail Shot — API Server

Backend API server. Port 8288 (behind nginx + SSL).

GET /api/health — health check (no auth)
POST /api/auth/login — legacy static bearer token
POST /api/auth/signup — email + password + authCode (Firebase Auth)
GET|POST /api/skus, GET /api/skus/{id} (per-user)
POST /api/skus/{id}/sources (multipart), POST /api/skus/{id}/generate
/admin/auth-codes — 회원가입 인증 코드 관리 (ADMIN_PASSWORD 필요)