feat: 添加内容可见性字段和过滤选项，优化内容列表查询功能

frontend/portal/src/views/creator/ContentsView.vue

@@ -18,6 +18,14 @@
                <option v-for="opt in statusOptions" :key="opt.key" :value="opt.key">{{ opt.value }}</option>
             </select>
          </div>
+         <div class="flex items-center gap-2">
+            <span class="text-sm font-bold text-slate-500">可见性:</span>
+            <select v-model="filterVisibility"
+               class="h-9 px-3 rounded border border-slate-200 text-sm focus:border-primary-500 outline-none bg-white cursor-pointer min-w-[100px]">
+               <option value="all">全部</option>
+               <option v-for="opt in visibilityOptions" :key="opt.key" :value="opt.key">{{ opt.value }}</option>
+            </select>
+         </div>
          <div class="flex items-center gap-2">
             <span class="text-sm font-bold text-slate-500">曲种:</span>
             <select v-model="filterGenre"
@@ -77,6 +85,9 @@
                      </div>
                      <!-- Status Badge -->
                      <div class="flex items-center gap-2 ml-4">
+                        <span class="text-[10px] px-1.5 py-0.5 rounded border border-slate-200 text-slate-500 bg-slate-50" v-if="item.visibility">
+                           {{ getVisibilityLabel(item.visibility) }}
+                        </span>
                         <span v-if="item.status === 'blocked'" class="text-red-500 text-xs flex items-center gap-1 cursor-help"
                            title="已被封禁">
                            <i class="pi pi-info-circle"></i> 封禁
@@ -173,10 +184,16 @@ const toast = useToast();
 const confirm = useConfirm();
 const contents = ref([]);
 const filterStatus = ref('all');
+const filterVisibility = ref('all');
 const filterGenre = ref('all');
 const filterKey = ref('all');
 const searchKeyword = ref('');
 const statusOptions = ref([]);
+const visibilityOptions = [
+    { key: 'public', value: '公开' },
+    { key: 'tenant_only', value: '仅会员' },
+    { key: 'private', value: '私有' }
+];
 const genreOptions = ref([]);
 const keys = ['C大调', 'D大调', 'E大调', 'F大调', 'G大调', 'A大调', 'B大调', '降E大调'];
 
@@ -196,6 +213,7 @@ const fetchContents = async () => {
    try {
       const params = {};
       if (filterStatus.value !== 'all') params.status = filterStatus.value;
+      if (filterVisibility.value !== 'all') params.visibility = filterVisibility.value;
       if (filterGenre.value !== 'all') params.genre = filterGenre.value;
       if (filterKey.value !== 'all') params.key = filterKey.value;
       if (searchKeyword.value) params.keyword = searchKeyword.value;
@@ -212,7 +230,7 @@ onMounted(() => {
    fetchContents();
 });
 
-watch([filterStatus, filterGenre, filterKey], () => {
+watch([filterStatus, filterVisibility, filterGenre, filterKey], () => {
    fetchContents();
 });
 
@@ -225,6 +243,15 @@ const getGenreLabel = (key) => {
     return opt ? opt.value : key;
 };
 
+const getVisibilityLabel = (vis) => {
+    const map = {
+        'public': '公开',
+        'tenant_only': '仅会员',
+        'private': '私有'
+    };
+    return map[vis] || vis;
+};
+
 const statusStyle = (status) => {
    // Map backend status to UI style. Labels should ideally come from backend option value/label map if needed,
    // but for style/color mapping we can keep it here or use a helper.