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>

server/internal/shared/objectstorage/reloadable.go

@@ -47,6 +47,55 @@ func (c *ReloadableClient) PublicURL(objectKey string) (string, error) {
 	return c.snapshot().PublicURL(objectKey)
 }
 
+func (c *ReloadableClient) DownloadURL(objectKey string) (string, error) {
+	return c.snapshot().DownloadURL(objectKey)
+}
+
+func (c *ReloadableClient) List(ctx context.Context, in ListInput) (*ListResult, error) {
+	client := c.snapshot()
+	management, ok := client.(ManagementClient)
+	if !ok {
+		return nil, ErrNotConfigured
+	}
+	return management.List(ctx, in)
+}
+
+func (c *ReloadableClient) Stat(ctx context.Context, objectKey string) (*ObjectInfo, error) {
+	client := c.snapshot()
+	management, ok := client.(ManagementClient)
+	if !ok {
+		return nil, ErrNotConfigured
+	}
+	return management.Stat(ctx, objectKey)
+}
+
+func (c *ReloadableClient) Copy(ctx context.Context, sourceKey, destinationKey string) error {
+	client := c.snapshot()
+	management, ok := client.(ManagementClient)
+	if !ok {
+		return ErrNotConfigured
+	}
+	return management.Copy(ctx, sourceKey, destinationKey)
+}
+
+func (c *ReloadableClient) Usage(ctx context.Context) (*UsageInfo, error) {
+	client := c.snapshot()
+	usageClient, ok := client.(UsageClient)
+	if !ok {
+		return nil, ErrUsageUnsupported
+	}
+	return usageClient.Usage(ctx)
+}
+
+func (c *ReloadableClient) PublicReadableURL(objectKey string) (string, error) {
+	client := c.snapshot()
+	publicClient, ok := client.(PublicReadableClient)
+	if !ok {
+		return "", ErrObjectNotPublic
+	}
+	return publicClient.PublicReadableURL(objectKey)
+}
+
 func (c *ReloadableClient) snapshot() Client {
 	if c == nil {
 		return disabledClient{reason: "object storage client is nil"}