feat: implement Phase 2 core features

- Add document CRUD API (list/get/upload/update/delete with auth)
  - Upload saves to Inbox + auto-enqueues processing pipeline
  - Delete defaults to DB-only, explicit flag for file deletion
- Add hybrid search API (FTS 0.4 + trigram 0.2 + vector 0.4 weighted)
  - Modes: fts, trgm, vector, hybrid (default)
  - Vector search gracefully degrades if GPU unavailable
- Add Inbox file watcher (5min interval, new file + hash change detection)
- Register documents/search routers and file_watcher scheduler in main.py
- Add IVFFLAT vector index migration (lists=50, with tuning guide)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/main.py

@@ -7,6 +7,8 @@ from fastapi.responses import RedirectResponse
 from sqlalchemy import func, select, text
 
 from api.auth import router as auth_router
+from api.documents import router as documents_router
+from api.search import router as search_router
 from api.setup import router as setup_router
 from core.config import settings
 from core.database import async_session, engine, init_db
@@ -17,14 +19,16 @@ from models.user import User
 async def lifespan(app: FastAPI):
     """앱 시작/종료 시 실행되는 lifespan 핸들러"""
     from apscheduler.schedulers.asyncio import AsyncIOScheduler
+    from workers.file_watcher import watch_inbox
     from workers.queue_consumer import consume_queue
 
     # 시작: DB 연결 확인
     await init_db()
 
-    # APScheduler: 큐 소비자 1분 간격 실행
+    # APScheduler: 백그라운드 작업
     scheduler = AsyncIOScheduler()
     scheduler.add_job(consume_queue, "interval", minutes=1, id="queue_consumer")
+    scheduler.add_job(watch_inbox, "interval", minutes=5, id="file_watcher")
     scheduler.start()
 
     yield
@@ -44,10 +48,10 @@ app = FastAPI(
 # ─── 라우터 등록 ───
 app.include_router(setup_router, prefix="/api/setup", tags=["setup"])
 app.include_router(auth_router, prefix="/api/auth", tags=["auth"])
+app.include_router(documents_router, prefix="/api/documents", tags=["documents"])
+app.include_router(search_router, prefix="/api/search", tags=["search"])
 
-# TODO: Phase 2에서 추가
-# app.include_router(documents.router, prefix="/api/documents", tags=["documents"])
-# app.include_router(search.router, prefix="/api/search", tags=["search"])
+# TODO: Phase 3~4에서 추가
 # app.include_router(tasks.router, prefix="/api/tasks", tags=["tasks"])
 # app.include_router(dashboard.router, prefix="/api/dashboard", tags=["dashboard"])
 # app.include_router(export.router, prefix="/api/export", tags=["export"])