feat(ops): add object storage management and site-mapping CSV import/export

Ship the Ops backstage 对象存储 page (browse / upload / move / delete /
folder ops) backed by a new object-storage service + handler, with the
shared storage client extended with List/Stat/Copy/Usage/DownloadURL so
both MinIO and Aliyun providers cover the new surface. Add
ForcePathStyle to the object-storage config and treat r2/s3/custom_s3
as external providers so Cloudflare R2 and other S3-compatibles can
share the MinIO client path without spinning up the bundled MinIO.

Also add CSV import/export + template download to the site-domain
mappings page, raise gin MaxMultipartMemory to 8 MiB for the new
multipart endpoints, register Ops swagger routes, and extend the
descriptions-parity test to cover the ops router.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

deploy/OFFLINE_PACKAGE.md

@@ -23,7 +23,9 @@ docker compose -f docker-compose.yaml -f docker-compose.offline.yaml --env-file
 Object storage is selected from `config.yaml` / `config.yml`, with `config.local.yaml` / `config.local.yml` as an override:
 
 - `object_storage.provider: minio` or `mino` deploys MinIO and `minio-init`
-- `object_storage.provider: aliyun`, `aliyun_oss`, `aliyun-oss`, or `oss` skips MinIO and uses the Aliyun OSS config from the same config files
+- `object_storage.provider: aliyun`, `aliyun_oss`, `aliyun-oss`, `oss`, `r2`, `cloudflare_r2`, `s3`, `aws_s3`, or `custom_s3` skips MinIO and uses the external object storage config from the same config files
+
+For Cloudflare R2, set `object_storage.region: auto` and `object_storage.force_path_style: true`.
 
 Runtime services connect to Postgres through PgBouncer in `session` pooling mode. The one-shot `migrate` job still connects directly to `postgres` and `monitoring-postgres` so DDL and seed work do not go through the pooler.