feat: replace Cloudinary with MinIO for all media storage

- Create server/services/minio.ts: S3-compatible service (same interface as
  cloudinaryService) using @aws-sdk/client-s3 and MINIO_ENDPOINT env var
- Replace all cloudinaryService imports with minioService across routes.ts,
  routes/reels.ts, routes/remotion.ts, services/media-purge.ts
- Replace Cloudinary logo URL pattern (res.cloudinary.com/...) with
  buildMinioUrl() helper throughout all server routes
- GET /api/cloudinary/config now returns a logoUrl field (full MinIO URL)
  so clients never need to build the URL themselves
- Update settings pages (desktop + mobile): labels changed to MinIO
  (Bucket Name, Access Key, Secret Key)
- Update image-editor.tsx: remove Cloudinary URL transformation, use logoUrl
- Update media-utils.ts: simplify getVideoThumbnailUrl (no URL transforms)
- Add MINIO_ENDPOINT and MINIO_PUBLIC_URL to docker-compose.yml + .env.example
- DB table reuse: cloudinary_config.cloud_name = bucket, api_key = access key,
  api_secret = secret key — no migration needed

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

docker-compose.yml

@@ -43,6 +43,9 @@ services:
       # Configuration FFmpeg Service
       FFMPEG_API_URL: http://ffmpeg-api:8000
       FFMPEG_API_KEY: ${FFMPEG_API_KEY:-socialflow-secret-ffmpeg-key}
+      # Configuration MinIO (stockage fichiers)
+      MINIO_ENDPOINT: ${MINIO_ENDPOINT:-http://minio:9000}
+      MINIO_PUBLIC_URL: ${MINIO_PUBLIC_URL:-http://localhost:9000}
     networks:
       - internal
       - nginx_default