feat: update backend OCR parser, web app, mobile app camera/preview UI, tests, and documentation with sample images

docker-compose.yml

@@ -117,6 +117,21 @@ services:
       - ./backend/db/migrations:/docker-entrypoint-initdb.d:ro
     restart: unless-stopped
 
+  # ─── Dev Tunnel ────────────────────────────────────────────────────────────
+  # Exposes the app via Cloudflare Quick Tunnel — no account needed.
+  # After startup, run:  docker logs paddleocr-tunnel
+  # Look for a line like:  https://xxxx-xxxx.trycloudflare.com
+  # Share that URL with Android devices on any network.
+  tunnel:
+    image: cloudflare/cloudflared:latest
+    container_name: paddleocr-tunnel
+    command: tunnel --no-autoupdate --url http://paddleocr-nginx:80
+    depends_on:
+      - nginx
+    restart: unless-stopped
+    profiles:
+      - tunnel   # opt-in: start with  docker compose --profile tunnel up
+
 volumes:
   hf_cache:
     name: paddleocr_hf_cache