sync(theme-3): 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-3 样式。

apps/admin/src/components/ContentRichEditor.vue

@@ -3,6 +3,8 @@ import { ref, watch, onMounted, onBeforeUnmount, nextTick } from 'vue';
 import { ElMessage } from 'element-plus';
 import { useAdminLocale } from '../composables/useAdminLocale';
 import api from '../api';
+import { fetchMediaLibraryImages } from '../utils/media-library';
+import { resolveApiError } from '../i18n/form-validation';
 
 const props = withDefaults(
   defineProps<{
@@ -27,7 +29,7 @@ const editorRef = ref<HTMLDivElement | null>(null);
 const mediaPickerVisible = ref(false);
 /** blob/object URL -> File，保存时由父组件调用 uploadPendingImages 上传 */
 const pendingFiles = new Map<string, File>();
-const mediaFiles = ref<Array<{ id: string; filename: string; url: string; mimeType: string }>>([]);
+const mediaFiles = ref<Array<{ id: string; filename: string; url: string; mimeType: string; category?: string }>>([]);
 const mediaLoading = ref(false);
 const syncing = ref(false);
 let savedRange: Range | null = null;
@@ -241,12 +243,10 @@ async function openMediaPicker() {
   mediaPickerVisible.value = true;
   mediaLoading.value = true;
   try {
-    const res = await api.get('/admin/files', {
-      params: { category: props.uploadCategory, pageSize: 200 },
-    });
-    mediaFiles.value = res.data.data.items ?? [];
-  } catch {
+    mediaFiles.value = await fetchMediaLibraryImages({ pageSize: 200 });
+  } catch (err: unknown) {
     mediaFiles.value = [];
+    ElMessage.error(resolveApiError(err, t, 'content.upload.load_media_failed'));
   } finally {
     mediaLoading.value = false;
   }
@@ -352,6 +352,7 @@ onBeforeUnmount(() => {
     width="680px"
     destroy-on-close
     append-to-body
+    :z-index="4000"
   >
     <div v-if="mediaLoading" class="media-state">{{ t('common.loading') }}</div>
     <div v-else-if="mediaFiles.length === 0" class="media-state">{{ t('content.upload.no_media') }}</div>
@@ -367,6 +368,7 @@ onBeforeUnmount(() => {
           <div v-else class="media-svg">SVG</div>
         </div>
         <div class="media-name" :title="file.filename">{{ file.filename }}</div>
+        <div v-if="file.category" class="media-category">{{ file.category }}</div>
       </div>
     </div>
   </el-dialog>
@@ -521,11 +523,18 @@ onBeforeUnmount(() => {
 }
 
 .media-name {
-  padding: 6px 8px;
+  padding: 6px 8px 2px;
   font-size: 11px;
   color: var(--text-muted);
   white-space: nowrap;
   overflow: hidden;
   text-overflow: ellipsis;
 }
+
+.media-category {
+  padding: 0 8px 6px;
+  font-size: 10px;
+  color: var(--text-muted);
+  opacity: 0.85;
+}
 </style>