feat(music-lab): wire redis client + internal_router + compose env (SP-6)

main.py에 redis.asyncio client 추가 + internal_router include.
docker-compose의 music-lab에 REDIS_URL/INTERNAL_API_KEY/MUSIC_RENDER_URL.
SUNO_API_KEY 라인 제거 (spec §9 — Windows로 이전).
Plan-B-Music Phase 1.

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

docker-compose.yml

@@ -62,7 +62,6 @@ services:
     environment:
       - TZ=${TZ:-Asia/Seoul}
       - MUSIC_AI_SERVER_URL=${MUSIC_AI_SERVER_URL:-}
-      - SUNO_API_KEY=${SUNO_API_KEY:-}
       - MUSIC_MEDIA_BASE=${MUSIC_MEDIA_BASE:-/media/music}
       - CORS_ALLOW_ORIGINS=${CORS_ALLOW_ORIGINS:-http://localhost:3007,http://localhost:8080}
       - PEXELS_API_KEY=${PEXELS_API_KEY:-}
@@ -77,9 +76,14 @@ services:
       - WINDOWS_VIDEO_ENCODER_URL=${WINDOWS_VIDEO_ENCODER_URL:-}
       - NAS_VIDEOS_ROOT=${NAS_VIDEOS_ROOT:-/volume1/docker/webpage/data/videos}
       - NAS_MUSIC_ROOT=${NAS_MUSIC_ROOT:-/volume1/docker/webpage/data/music}
+      - REDIS_URL=${REDIS_URL:-redis://redis:6379}
+      - INTERNAL_API_KEY=${INTERNAL_API_KEY:-}
+      - MUSIC_RENDER_URL=${MUSIC_RENDER_URL:-http://192.168.45.59:18711}
     volumes:
       - ${RUNTIME_PATH}/data/music:/app/data
       - ${RUNTIME_PATH:-.}/data/videos:/app/data/videos
+    depends_on:
+      - redis
     healthcheck:
       test: ["CMD", "python", "-c", "import urllib.request; urllib.request.urlopen('http://localhost:8000/health')"]
       interval: 60s