feat: 编辑器锁定文章提示 - 禁用编辑，显示明确提示

- /studio/write?id=X 路由：文章被锁定时，页面显示紫色锁定横幅，标题/编辑器只读，提交按钮替换为锁定提示
- studio-editor.js：锁定态下 Vditor 设为 readonly 模式，隐藏工具栏，禁用 Ctrl+S 快捷键
- 新增 .studio-locked-banner / .locked-submit-hint 样式

templates/MetaLab-2026/html/studio/write.html

@@ -8,9 +8,20 @@
 
     <main class="studio-main">
         <div class="editor-layout">
+            {{if and .Post .Post.IsLocked}}
+            <div class="studio-locked-banner">
+                <div class="locked-banner-icon">🔒</div>
+                <div>
+                    <strong>这篇文章已被锁定，无法编辑。</strong>
+                    <p>如需解锁请联系管理员。当前状态：{{if $.StatusNames}}{{index $.StatusNames .Post.Status}}、已锁定{{end}}</p>
+                </div>
+            </div>
+            {{end}}
+
             <form id="postForm" class="editor-form">
                 <input type="hidden" id="postId" value="{{if .Post}}{{.Post.ID}}{{end}}">
                 {{if .Post}}
+                <input type="hidden" id="isLocked" value="{{if .Post.IsLocked}}1{{else}}0{{end}}">
                 <textarea id="editBody" style="display:none">{{.Post.Body}}</textarea>
                 {{end}}
 
@@ -18,7 +29,8 @@
                     <input type="text" id="postTitle" class="editor-title-input"
                         value="{{if .Post}}{{.Post.Title}}{{end}}"
                         placeholder="输入文章标题..."
-                        maxlength="200" required autofocus>
+                        maxlength="200" required autofocus
+                        {{if and .Post .Post.IsLocked}}disabled{{end}}>
                 </div>
 
                 <div class="editor-main">
@@ -55,7 +67,11 @@
                     <span class="status-item" id="wordCount">0 字</span>
                     <span class="status-item status-draft" id="draftStatus" style="display:none">草稿已保存</span>
                     <span class="status-spacer"></span>
+                    {{if and .Post .Post.IsLocked}}
+                    <span class="locked-submit-hint">🔒 此文已锁定，无法修改</span>
+                    {{else}}
                     <button type="submit" class="btn btn-primary btn-submit">{{if .Post}}保存修改{{else}}发布帖子{{end}}</button>
+                    {{end}}
                 </div>
             </form>
         </div>