docs: 全面更新 README 与站点到 v0.2.5 最终状态

README:
- badge 测试数 768→780，目录补语法高亮章节
- 特性修正：解析器 99% 行覆盖、六语言、16 个高亮语言标识
- 事件表补 selectionChange / cursorMove
- 插件表补 exportPDF / searchReplace 大小写全字 / imagePaste maxSizeKB
- XSS 章节补属性级注入防护说明
- 构建章节补 npm run bench
- 源码结构补 5 个新模块（commands/floating-toolbar/context-menu/outline/highlight）

site:
- index.html: 测试数/gzip 体积更正（42KB）、新增语法高亮特性卡、
  光标选区 API 速览卡、六语言文案
- demo.html: 启用内置高亮（highlight: MeEditor.highlight）、
  新增 python/bash 代码块演示、v0.2.5 真实新特性列表、17 源文件/780 测试
- docs.html: 高亮章节补 16 标识与 CSS 定制示例、exportPDF/maxSizeKB/
  大小写全字说明、XSS 属性注入、静态 API 补 highlight 导入

src:
- styles.ts: 新增 me-hl-* 高亮配色（深浅色自适应）
- 修复复查引入的 TS 错误（普通函数 this 返回类型非法）

site/index.html

@@ -109,7 +109,7 @@ footer a:hover{text-decoration:underline}
     <span class="badge accent">v0.2.5</span>
     <span class="badge">TypeScript</span>
     <span class="badge">零运行时依赖</span>
-    <span class="badge">768 tests</span>
+    <span class="badge">780 tests</span>
     <span class="badge">桌面端优先</span>
     <span class="badge">MIT</span>
   </div>
@@ -120,8 +120,8 @@ footer a:hover{text-decoration:underline}
   <div class="stats">
     <div class="stat"><div class="stat-num">0</div><div class="stat-label">运行时依赖</div></div>
     <div class="stat"><div class="stat-num">99%</div><div class="stat-label">解析器行覆盖</div></div>
-    <div class="stat"><div class="stat-num">768</div><div class="stat-label">单元测试</div></div>
-    <div class="stat"><div class="stat-num">~30KB</div><div class="stat-label">gzip 体积</div></div>
+    <div class="stat"><div class="stat-num">780</div><div class="stat-label">单元测试</div></div>
+    <div class="stat"><div class="stat-num">~42KB</div><div class="stat-label">gzip 体积</div></div>
   </div>
 </header>
 
@@ -144,8 +144,9 @@ footer a:hover{text-decoration:underline}
       <div class="feature"><div class="feature-icon"><svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><rect x="3" y="3" width="18" height="18" rx="2"/><line x1="12" y1="3" x2="12" y2="21"/></svg></div><h3>分屏实时预览</h3><p>edit / split / preview 三模式切换，拖拽分隔条调整比例，双向比例同步滚动。</p></div>
       <div class="feature"><div class="feature-icon"><svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 2L2 7l10 5 10-5-10-5z"/><path d="M2 17l10 5 10-5"/><path d="M2 12l10 5 10-5"/></svg></div><h3>零运行时依赖</h3><p>不依赖任何第三方运行时库，打包后单文件，UMD / ESM / CJS 三种格式开箱即用。</p></div>
       <div class="feature"><div class="feature-icon"><svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="3"/><path d="M19.4 15a1.65 1.65 0 0 0 .33 1.82l.06.06a2 2 0 0 1 0 2.83 2 2 0 0 1-2.83 0l-.06-.06a1.65 1.65 0 0 0-1.82-.33 1.65 1.65 0 0 0-1 1.51V21a2 2 0 0 1-4 0v-.09A1.65 1.65 0 0 0 9 19.4a1.65 1.65 0 0 0-1.82.33l-.06.06a2 2 0 0 1-2.83 0 2 2 0 0 1 0-2.83l.06-.06a1.65 1.65 0 0 0 .33-1.82 1.65 1.65 0 0 0-1.51-1H3a2 2 0 0 1 0-4h.09A1.65 1.65 0 0 0 4.6 9a1.65 1.65 0 0 0-.33-1.82l-.06-.06a2 2 0 0 1 0-2.83 2 2 0 0 1 2.83 0l.06.06a1.65 1.65 0 0 0 1.82.33H9a1.65 1.65 0 0 0 1-1.51V3a2 2 0 0 1 4 0v.09a1.65 1.65 0 0 0 1 1.51 1.65 1.65 0 0 0 1.82-.33l.06-.06a2 2 0 0 1 2.83 0 2 2 0 0 1 0 2.83l-.06.06a1.65 1.65 0 0 0-.33 1.82V9a1.65 1.65 0 0 0 1.51 1H21a2 2 0 0 1 0 4h-.09a1.65 1.65 0 0 0-1.51 1z"/></svg></div><h3>6 个预设插件</h3><p>autoSave / exportTool / searchReplace / imagePaste / shortcutHelp / fileSystem，插件 v2 支持拓扑排序、异步、卸载。</p></div>
-      <div class="feature"><div class="feature-icon"><svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="5"/><line x1="12" y1="1" x2="12" y2="3"/><line x1="12" y1="21" x2="12" y2="23"/><line x1="4.22" y1="4.22" x2="5.64" y2="5.64"/><line x1="18.36" y1="18.36" x2="19.78" y2="19.78"/><line x1="1" y1="12" x2="3" y2="12"/><line x1="21" y1="12" x2="23" y2="12"/></svg></div><h3>主题 & i18n</h3><p>4 套预设主题 + CSS 变量定制 + 实例级隔离。中英双语开箱即用，支持远程加载翻译包。</p></div>
-      <div class="feature"><div class="feature-icon"><svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 22s8-4 8-10V5l-8-3-8 3v7c0 6 8 10 8 10z"/></svg></div><h3>XSS 安全防护</h3><p>HTML 转义、危险协议过滤、sanitize 钩子、highlight 异常回退。多层防护，安全可靠。</p></div>
+      <div class="feature"><div class="feature-icon"><svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="5"/><line x1="12" y1="1" x2="12" y2="3"/><line x1="12" y1="21" x2="12" y2="23"/><line x1="4.22" y1="4.22" x2="5.64" y2="5.64"/><line x1="18.36" y1="18.36" x2="19.78" y2="19.78"/><line x1="1" y1="12" x2="3" y2="12"/><line x1="21" y1="12" x2="23" y2="12"/></svg></div><h3>主题 & i18n</h3><p>4 套预设主题 + CSS 变量定制 + 实例级隔离。六种语言开箱即用（中 / 英 / 日 / 韩 / 法 / 德），支持远程加载翻译包。</p></div>
+      <div class="feature"><div class="feature-icon"><svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="16 18 22 12 16 6"/><polyline points="8 6 2 12 8 18"/></svg></div><h3>内置语法高亮</h3><p>零依赖轻量高亮器，js / ts / python / bash / css 等 16 个语言标识，代码块一行配置即自动着色。</p></div>
+      <div class="feature"><div class="feature-icon"><svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 22s8-4 8-10V5l-8-3-8 3v7c0 6 8 10 8 10z"/></svg></div><h3>XSS 安全防护</h3><p>HTML 转义、危险协议过滤、属性级注入防护、sanitize 钩子、highlight 异常回退。多层防护，安全可靠。</p></div>
     </div>
   </div>
 </section>
@@ -188,7 +189,8 @@ editor<span class="c-punc">.</span><span class="c-fn">exec</span><span class="c-
     <span class="section-eyebrow">API Reference</span>
     <h2 class="section-title">API 速览</h2>
     <div class="api-grid">
-      <div class="api-card"><h4>内容操作</h4><ul><li>getValue() <span class="ret">string</span></li><li>setValue(md) <span class="ret">this</span></li><li>getHTML() <span class="ret">string</span></li><li>insert(text) <span class="ret">this</span></li><li>wrap(before, after) <span class="ret">this</span></li><li>focus() / blur() <span class="ret">this</span></li></ul></div>
+      <div class="api-card"><h4>内容操作</h4><ul><li>getValue() <span class="ret">string</span></li><li>setValue(md) <span class="ret">this</span></li><li>getHTML() <span class="ret">string</span></li><li>insert(text) <span class="ret">this</span></li><li>wrap(before, after) <span class="ret">this</span></li><li>replaceAll(search, rep) <span class="ret">number</span></li></ul></div>
+      <div class="api-card"><h4>光标与选区</h4><ul><li>getSelectedText() <span class="ret">string</span></li><li>getCursorPosition() <span class="ret">{line,column}</span></li><li>setCursorPosition(l, c) <span class="ret">this</span></li><li>selectLine(n) / selectAll() <span class="ret">this</span></li><li>toggleFloatingToolbar() <span class="ret">this</span></li></ul></div>
       <div class="api-card"><h4>命令执行</h4><ul><li>exec(action) <span class="ret">this</span></li><li>undo() / redo() <span class="ret">this</span></li><li>canUndo() / canRedo() <span class="ret">boolean</span></li></ul></div>
       <div class="api-card"><h4>模式与全屏</h4><ul><li>setMode(mode) <span class="ret">this</span></li><li>getMode() <span class="ret">string</span></li><li>toggleFullscreen() <span class="ret">this</span></li><li>toggleZen() <span class="ret">this</span></li></ul></div>
       <div class="api-card"><h4>事件与插件</h4><ul><li>on(event, fn) <span class="ret">unsub</span></li><li>off(event, fn) <span class="ret">this</span></li><li>use(plugin) <span class="ret">this</span></li><li>unuse(name) <span class="ret">this</span></li><li>addToolbarButton(cfg) <span class="ret">this</span></li></ul></div>