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>

nginx/nginx.conf

@@ -25,8 +25,8 @@ server {
         proxy_send_timeout 120s;
     }
 
-    # SSE 스트리밍 전용 (버퍼링 OFF)
-    location ~ ^/api/inspections/[^/]+/stream$ {
+    # SSE 스트리밍 전용 (모든 검사 타입: 단일/사이트/배치)
+    location ~ ^/api/(inspections|site-inspections|batch-inspections)/[^/]+/stream$ {
         proxy_pass http://backend;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
@@ -36,7 +36,7 @@ server {
 
         proxy_buffering off;
         proxy_cache off;
-        proxy_read_timeout 300s;
+        proxy_read_timeout 600s;
         chunked_transfer_encoding off;
 
         # SSE content type