feat(video-lab): docker-compose entry + nginx routing (SP-8)

video-lab service: port 18801, REDIS_URL/INTERNAL_API_KEY env,
depends_on redis, /app/data volume mount.
nginx: /api/video/ proxy + /media/video/ direct serve alias.
frontend depends_on + volume mount 추가.
Plan-B-Video Phase 1.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

nginx/default.conf

@@ -36,6 +36,17 @@ server {
     autoindex off;
   }
 
+  # video media — Nginx 직접 mp4 서빙
+  location ^~ /media/video/ {
+    alias /data/video/;
+
+    expires 1d;
+    add_header Cache-Control "public, max-age=86400" always;
+    add_header Accept-Ranges bytes always;
+
+    autoindex off;
+  }
+
   # music videos — Nginx가 직접 비디오 파일 서빙
   location ^~ /media/insta/ {
     alias /data/insta_cards/;
@@ -68,6 +79,21 @@ server {
     proxy_pass http://$music_backend$request_uri;
   }
 
+  # video-lab — 영상 생성 gateway
+  location /api/video/ {
+    resolver 127.0.0.11 valid=10s;
+    set $video_backend video-lab:8000;
+
+    proxy_http_version 1.1;
+    proxy_set_header Host $host;
+    proxy_set_header X-Real-IP $remote_addr;
+    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+    proxy_pass http://$video_backend$request_uri;
+
+    proxy_read_timeout 120s;
+    proxy_connect_timeout 10s;
+  }
+
   # realestate API
   location /api/realestate/ {
     proxy_http_version 1.1;