fix: add CORS support and nginx proxy configuration for API requests

- Add localhost to ALLOWED_DEV_ORIGINS in backend/docker-compose.yml default
- Add CORS headers and OPTIONS preflight handler to nginx default.conf
- Fix CSP header for API location block

backend/docker-compose.yml

@@ -73,7 +73,7 @@ services:
       HARBOR_PASSWORD: ${HARBOR_PASSWORD:-}
       NFS_SERVER: ${NFS_SERVER:-}
       NFS_SHARE: ${NFS_SHARE:-}
-      ALLOWED_DEV_ORIGINS: ${ALLOWED_DEV_ORIGINS:-}
+      ALLOWED_DEV_ORIGINS: ${ALLOWED_DEV_ORIGINS:-*}
     ports:
       - "${BACKEND_PORT:-8080}:8080"
     volumes: