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/static/js/studio-editor.js

@@ -18,6 +18,7 @@ document.addEventListener('DOMContentLoaded', () => {
 
     const postId = document.getElementById('postId')?.value
     const isEdit = !!postId
+    const isLocked = document.getElementById('isLocked')?.value === '1'
 
     let initialMD = ''
     const editBodyEl = document.getElementById('editBody')
@@ -30,9 +31,10 @@ document.addEventListener('DOMContentLoaded', () => {
         cdn: '/static/vditor',
         height: '100%',
         lang: 'zh_CN',
-        placeholder: '在此输入正文...',
+        placeholder: isLocked ? '此文已锁定，不可编辑' : '在此输入正文...',
+        readonly: isLocked,
 
-        toolbar: [
+        toolbar: isLocked ? [] : [
             'headings', 'bold', 'italic', 'strike', '|',
             'line', 'code', 'inline-code', 'link', 'quote', '|',
             'list', 'ordered-list', 'check', 'outdent', 'indent', '|',
@@ -100,12 +102,14 @@ document.addEventListener('DOMContentLoaded', () => {
 
     document.getElementById('postForm')?.addEventListener('submit', handleSubmit)
 
-    document.addEventListener('keydown', (e) => {
-        if ((e.ctrlKey || e.metaKey) && e.key === 's') {
-            e.preventDefault()
-            document.getElementById('postForm')?.dispatchEvent(new Event('submit'))
-        }
-    })
+    if (!isLocked) {
+        document.addEventListener('keydown', (e) => {
+            if ((e.ctrlKey || e.metaKey) && e.key === 's') {
+                e.preventDefault()
+                document.getElementById('postForm')?.dispatchEvent(new Event('submit'))
+            }
+        })
+    }
 })
 
 function updateWordCount() {