sync(theme-2): 同步 main 最新 API/Admin 与玩家端逻辑

从 main 同步站内信手动发送、媒体库选择、列表子路由重构等 API/Admin 改动；玩家端仅合并 ADMIN_CUSTOM 富文本、消息预览与充值截图压缩逻辑，保留 theme-2 样式。

apps/admin/src/App.vue

@@ -65,6 +65,7 @@ body::-webkit-scrollbar {
   height: 100%;
   min-height: 0;
   overflow: hidden;
+  gap: 14px;
 }
 .admin-list-page > .page-toolbar,
 .admin-list-page > .filter-card,
@@ -78,16 +79,16 @@ body::-webkit-scrollbar {
   justify-content: flex-end;
   align-items: center;
   gap: 8px;
-  margin: 0 0 8px;
+  margin: 0;
 }
 .admin-list-page > .tool-card {
-  margin-bottom: 8px;
+  margin-bottom: 0;
 }
 .admin-list-page > .filter-card {
-  margin-bottom: 8px;
+  margin-bottom: 0;
 }
 .admin-list-page > .list-chrome {
-  margin-bottom: 8px;
+  margin-bottom: 0;
   display: flex;
   flex-direction: column;
   gap: 6px;
@@ -204,7 +205,7 @@ body::-webkit-scrollbar {
   margin-right: 0;
 }
 .admin-list-page > .list-settings {
-  margin-bottom: 8px;
+  margin-bottom: 0;
 }
 .list-settings :deep(.el-collapse-item__header) {
   height: 36px;
@@ -250,7 +251,16 @@ body::-webkit-scrollbar {
   min-height: 0;
   display: flex;
   flex-direction: column;
-  padding: 0 12px 12px;
+  padding: 12px;
+}
+
+/* data-card 内不再嵌套第二层卡片边框，避免双层顶边重合 */
+.admin-list-page > .data-card .table-wrap,
+.admin-list-page > .data-card .admin-table-wrap {
+  border: none;
+  border-radius: 0;
+  box-shadow: none;
+  background: transparent;
 }
 .admin-list-page .table-wrap {
   flex: 1;