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/bootstrap/http_test.go

@@ -20,6 +20,7 @@ func TestNewEngineUsesForwardedClientIPFromTrustedProxy(t *testing.T) {
 		TrustedProxies: []string{"10.42.0.0/16"},
 	})
 	require.NoError(t, err)
+	require.Equal(t, int64(MaxMultipartMemory), engine.MaxMultipartMemory)
 
 	engine.GET("/ip", func(c *gin.Context) {
 		c.String(http.StatusOK, c.ClientIP())