feat: Phase 0-2 complete — auth, machines, equipment parts with full CRUD

Multi-tenant factory inspection system (SpiFox, Enkid, Alpet):
- FastAPI backend with JWT auth, PostgreSQL (asyncpg)
- Next.js 16 frontend with App Router, SWR data fetching
- Machines CRUD with equipment parts management
- Part lifecycle tracking (hours/count/date) with counters
- Partial unique index for soft-delete support
- 24 pytest tests passing, E2E verified

Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,20 @@
+# FactoryOps v2 환경 변수
+
+# PostgreSQL 연결 (필수)
+DATABASE_URL=postgresql+asyncpg://factoryops:factoryops@localhost:5432/factoryops_v2
+
+# 테스트 DB
+TEST_DATABASE_URL=postgresql+asyncpg://factoryops:factoryops@localhost:5432/factoryops_v2_test
+
+# SQL 쿼리 로깅 (디버깅용)
+# SQL_ECHO=true
+
+# JWT 시크릿 키 (프로덕션에서 반드시 변경)
+JWT_SECRET_KEY=your-super-secret-key-change-in-production
+
+# 서버 설정
+HOST=0.0.0.0
+PORT=8000
+
+# 프론트엔드 API URL
+NEXT_PUBLIC_API_URL=http://localhost:8000