fix(admin): surface partial Antigravity refresh warnings

Return the updated account alongside partial refresh warnings so the admin UI can keep its state current and tell operators when project ID retrieval must retry.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/internal/handler/admin/account_handler.go

@@ -1545,6 +1545,7 @@ func (h *AccountHandler) Refresh(c *gin.Context) {
 
 	if warning == "missing_project_id_temporary" {
 		response.Success(c, gin.H{
+			"account": h.buildAccountResponseWithRuntime(c.Request.Context(), updatedAccount),
 			"message": "Token refreshed successfully, but project_id could not be retrieved (will retry automatically)",
 			"warning": "missing_project_id_temporary",
 		})