feat: integrate FlareSolverr for Cloudflare bypass on clone sources

- Add FLARESOLVERR_URL env var to .env.example
- Update fetchSourceFurnidata to fall back to FlareSolverr on CF challenges (403/HTML)
- Add docker-compose.yml with FlareSolverr service
- Add scripts/health-check.sh for FlareSolverr readiness check
- Add health:check script to package.json
- Document FlareSolverr setup in README

docker-compose.yml

@@ -0,0 +1,11 @@
+version: "3.8"
+
+services:
+  flaresolverr:
+    image: flaresolverr/flaresolverr:latest
+    container_name: flaresolverr
+    ports:
+      - "8191:8191"
+    restart: unless-stopped
+    environment:
+      - LOG_LEVEL=info