Add NextSnap PWA with photo gallery viewer and continuous capture

Offline-first photo capture app for Nextcloud with:
- Camera capture with continuous mode (auto-reopens after each photo)
- File browser with fullscreen image gallery, swipe navigation, and rename
- Upload queue with background sync engine
- Admin panel for Nextcloud user management
- Service worker for offline-first caching (v13)

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

docker-compose.dev.yml

@@ -0,0 +1,38 @@
+version: '3.8'
+
+services:
+  nextsnap-dev:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    container_name: nextsnap-dev
+    ports:
+      - "${PORT:-5000}:5000"
+    environment:
+      - FLASK_ENV=development
+      - FLASK_DEBUG=true
+      - SECRET_KEY=dev-secret-key-not-for-production
+      - NEXTCLOUD_URL=${NEXTCLOUD_URL:-https://nextcloud.sdanywhere.com}
+      - TZ=${TZ:-UTC}
+    volumes:
+      - ./app:/app/app
+      - ./config.py:/app/config.py
+      - ./run.py:/app/run.py
+      - flask_sessions_dev:/tmp/flask_session
+    restart: unless-stopped
+    command: ["python", "run.py"]
+    networks:
+      - nextsnap-dev-network
+    logging:
+      driver: "json-file"
+      options:
+        max-size: "5m"
+        max-file: "2"
+
+volumes:
+  flask_sessions_dev:
+    driver: local
+
+networks:
+  nextsnap-dev-network:
+    driver: bridge