feat: 3-mode inspection with tabbed UI + batch upload

- Add batch inspection backend (multipart upload, SSE streaming, MongoDB)
- Add tabbed UI (single page / site crawling / batch upload) on home and history pages
- Add batch inspection progress, result pages with 2-panel layout
- Rename "사이트 전체" to "사이트 크롤링" across codebase
- Add python-multipart dependency for file upload
- Consolidate nginx SSE location for all inspection types

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/main.py

@@ -10,7 +10,7 @@ from fastapi.middleware.cors import CORSMiddleware
 
 from app.core.database import connect_db, close_db
 from app.core.redis import connect_redis, close_redis
-from app.routers import health, inspections, reports, site_inspections
+from app.routers import health, inspections, reports, site_inspections, batch_inspections
 
 # Configure logging
 logging.basicConfig(
@@ -57,3 +57,4 @@ app.include_router(health.router, prefix="/api", tags=["Health"])
 app.include_router(inspections.router, prefix="/api", tags=["Inspections"])
 app.include_router(reports.router, prefix="/api", tags=["Reports"])
 app.include_router(site_inspections.router, prefix="/api", tags=["Site Inspections"])
+app.include_router(batch_inspections.router, prefix="/api", tags=["Batch Inspections"])