feat: 文章属性前端完成 — Phase 3

- 写文章页：可见性/类型/转载来源/创作声明/禁止转载 属性表单
- 类型切换联动（转载显示来源，原创显示禁止转载复选框）
- 文章详情页：私密角标、置顶标记、创作声明横幅、转载来源
- 管理后台：置顶/取消置顶操作按钮
- PostService Create/Update 签名扩展接受文章属性
- DTO/接口同步更新

templates/MetaLab-2026/static/css/posts.css

@@ -1374,3 +1374,39 @@
     margin-top: 2px;
     padding-top: 6px;
 }
+
+/* --- 文章属性声明 --- */
+.post-declarations {
+    margin-top: 10px;
+    padding: 10px 14px;
+    background: #fffbeb;
+    border: 1px solid #fde68a;
+    border-radius: 6px;
+    display: flex;
+    flex-direction: column;
+    gap: 4px;
+}
+
+.post-declaration-item {
+    font-size: 13px;
+    color: #92400e;
+    line-height: 1.5;
+}
+
+.post-badge {
+    display: inline-block;
+    padding: 1px 8px;
+    border-radius: 4px;
+    font-size: 12px;
+    font-weight: 500;
+}
+
+.post-badge-private {
+    background: #f3f4f6;
+    color: #6b7280;
+}
+
+.post-badge-pinned {
+    background: #dbeafe;
+    color: #1d4ed8;
+}

templates/MetaLab-2026/static/css/studio.css

@@ -759,3 +759,48 @@
         width: 100%;
     }
 }
+
+/* --- Editor Meta (文章属性) --- */
+.editor-meta {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 8px 24px;
+    padding: 10px 16px;
+    background: #f9fafb;
+    border: 1px solid #e5e7eb;
+    border-radius: 8px;
+    margin-bottom: 12px;
+    font-size: 14px;
+}
+
+.meta-row {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+}
+
+.meta-label {
+    font-weight: 600;
+    color: #374151;
+    min-width: 40px;
+}
+
+.meta-radio {
+    display: flex;
+    align-items: center;
+    gap: 4px;
+    cursor: pointer;
+    color: #4b5563;
+}
+
+.meta-radio input[type="radio"] {
+    margin: 0;
+}
+
+.meta-checkbox {
+    display: flex;
+    align-items: center;
+    gap: 4px;
+    cursor: pointer;
+    color: #4b5563;
+}