feat: v0.4.3 — 浮动工具栏定位引擎重做 + 程序化编辑统一刷新管线

- 浮动工具栏 mirror 镜像测量：隐藏镜像层复制 textarea 排版样式，选区锚点插零宽字符读像素坐标，CJK/软换行/跨行选区误差全部消除

- 实测尺寸替代魔法数字；滚动 rAF 节流重定位；滚出视口自动隐藏；a11y：role=toolbar + aria-label、visibility 移出 Tab 序列、键盘可达

- 修复死开关/监听器泄漏/销毁后 focus 崩溃/blur 焦点抖动误隐藏

- _afterProgrammaticEdit 统一 8 条程序化路径的渲染/行号/字数/大纲/事件刷新；右键菜单 label 转义、copyAsHTML Firefox 降级、paste 失败提示、Esc 退出全屏

- 测试 871 → 895，e2e 22 → 28 项断言（含真实浏览器浮动工具栏布局验证）

site/docs.html

@@ -4,7 +4,7 @@
 <meta charset="UTF-8"/>
 <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
 <link rel="icon" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>📖</text></svg>"/>
-<title>MetonaEditor v0.4.2 · 文档</title>
+<title>MetonaEditor v0.4.3 · 文档</title>
 <style>
 *{box-sizing:border-box;margin:0;padding:0}
 :root{--bg:#0f1117;--bg-soft:#161922;--card:#1c2029;--card-hover:#232834;--text:#e6e8eb;--muted:#9ca3af;--accent:#3b82f6;--accent-2:#8b5cf6;--accent-soft:rgba(59,130,246,.12);--border:rgba(255,255,255,.08);--gradient:linear-gradient(135deg,#3b82f6 0%,#8b5cf6 50%,#ec4899 100%)}
@@ -65,7 +65,7 @@ footer a{color:var(--accent);text-decoration:none}
 
 <header class="docs-header">
   <h1><span class="grad">API 文档</span></h1>
-  <p class="sub">MetonaEditor v0.4.2 · TypeScript · 完整配置、API 与使用指南</p>
+  <p class="sub">MetonaEditor v0.4.3 · TypeScript · 完整配置、API 与使用指南</p>
 </header>
 
 <div class="container">
@@ -264,7 +264,7 @@ editor<span class="c-punc">.</span><span class="c-fn">setZenMaxWidth</span><span
 editor<span class="c-punc">.</span><span class="c-fn">getZenMaxWidth</span><span class="c-punc">();</span> <span class="c-com">// => number | string | false</span>
 editor<span class="c-punc">.</span><span class="c-fn">toggleWordWrap</span><span class="c-punc">();</span>  <span class="c-fn">setWordWrap</span><span class="c-punc">(</span><span class="c-kw">true</span><span class="c-punc">);</span>  <span class="c-fn">isWordWrap</span><span class="c-punc">();</span>
 editor<span class="c-punc">.</span><span class="c-fn">setOutline</span><span class="c-punc">(</span><span class="c-kw">true</span><span class="c-punc">);</span>  <span class="c-fn">isOutline</span><span class="c-punc">();</span>  <span class="c-com">// 运行时开关大纲面板（v0.4.2）</span>
-editor<span class="c-punc">.</span><span class="c-fn">toggleFloatingToolbar</span><span class="c-punc">();</span>  <span class="c-fn">isFloatingToolbar</span><span class="c-punc">();</span> <span class="c-com">// 选中文本格式栏</span></pre>
+editor<span class="c-punc">.</span><span class="c-fn">toggleFloatingToolbar</span><span class="c-punc">();</span>  <span class="c-fn">isFloatingToolbar</span><span class="c-punc">();</span> <span class="c-com">// 选中文本格式栏（mirror 镜像像素级定位，v0.4.3）</span></pre>
 </section>
 
 <section id="api-stats"><h3>统计与状态</h3>
@@ -533,7 +533,7 @@ i18nUtils<span class="c-punc">.</span><span class="c-fn">formatDate</span><span
 
 <footer>
   <div class="container">
-    MetonaEditor v0.4.2 · TypeScript · <a href="https://git.metona.cn/MetonaTeam/MetonaEditor" target="_blank" rel="noopener">源码仓库</a> · MIT License
+    MetonaEditor v0.4.3 · TypeScript · <a href="https://git.metona.cn/MetonaTeam/MetonaEditor" target="_blank" rel="noopener">源码仓库</a> · MIT License
   </div>
 </footer>