Add diagnostics for MKCOL failures in ensureParent method

go_cloud/internal/storage/webdav.go

@@ -77,11 +77,15 @@ func (c *WebDAVClient) ensureParent(ctx context.Context, remotePath string) erro
 		if err != nil {
 			return err
 		}
+		// Read body for diagnostics
+		b, _ := io.ReadAll(resp.Body)
 		resp.Body.Close()
 		// 201 created, 405 exists — ignore
 		if resp.StatusCode == 201 || resp.StatusCode == 405 {
 			continue
 		}
+		// Any other status is an error: return with diagnostics so caller can log and act on it
+		return fmt.Errorf("MKCOL failed for %s: status=%d body=%s", mkurl, resp.StatusCode, string(b))
 	}
 	return nil
 }