release: 发布 v0.5.1

新增能力：内置 4 套红头、3 套正式文档和 3 套标书主题，支持主题推荐页边距、页面装饰、页眉页脚和页码；增加结构化公文、项目报告及标书 Front Matter，内置 Fandol 中文字体、两份教程和 14 份主题示例。

桌面工作流：重组更多菜单，增加新建、保存、另存为快捷键和未保存确认；另存为后跟随新路径，主题示例自动切换主题，Desktop 发行包完整携带教程、示例与字体。

问题修复：修正红头标题居中与正式文档字体；围栏代码按正文宽度自动换行，长内容安全断行，至少两行即可在当前页分页，并统一保留 8px 左侧内容留白；Docker Web 镜像正确打包 samples。

兼容与部署：未声明主题推荐设置时继续使用 16mm 默认页边距；Web 隐藏不适用的另存为。正式镜像 yixiong/md-to-pdf:v0.5.1 内容 ID 为 sha256:72f519a69bfd6cb2f6df30c2be938e58ceb6f20e4748a32551874de3d436b276，Compose 健康运行。

验证结果：最终修复前 65 个测试文件、286 项测试通过，最终代码块与主题定向测试 27 项通过；全项目类型检查、生产构建和 git diff --check 通过。容器检出 14 套主题、17 份 Markdown，代码块回归 PDF 为 2 页且无越界。NSIS SHA-256 为 676CCE73D782B0B15AC6BC68F253CFBC4740383583E4DAA98F746EDF9999C5CC，ZIP SHA-256 为 82BF6ADF1200604F145CC86FA3ED193955CF6741EBEE3DF8953483515CFF621F。

apps/web/src/ExportSettingsDrawer.tsx

@@ -1,4 +1,5 @@
 import {
+  defaultExportConfig,
   getPaperDimensionsMm,
   lengthToMillimeters,
   paperFormatLabels,
@@ -12,9 +13,11 @@ import {
   type MermaidExportConfig
 } from "@md-to-pdf/core";
 import { useEffect, useState } from "react";
+import type { ThemeSummary } from "./application-backend";
 
 interface ExportSettingsDrawerProps {
   config: ExportConfig;
+  theme: ThemeSummary | undefined;
   onChange: (config: ExportConfig) => void;
   onClose: () => void;
   onReset: () => void;
@@ -24,6 +27,9 @@ interface LengthInputProps {
   label: string;
   value: string;
   maximum: number;
+  disabled?: boolean;
+  precision?: number;
+  step?: number;
   onChange: (value: string) => void;
 }
 
@@ -32,6 +38,7 @@ const pageNumberFormatLabels: Record<FooterConfig["format"], string> = {
   "page-total": "1 / 10",
   "chinese-page-total": "第 1 页 / 共 10 页",
   "dash-page": "- 1 -",
+  "official-page": "— 1 —（标准公文）",
   custom: "自定义模板"
 };
 
@@ -98,6 +105,9 @@ function LengthInput({
   label,
   value,
   maximum,
+  disabled = false,
+  precision = 1,
+  step = 0.1,
   onChange
 }: LengthInputProps) {
   const [draft, setDraft] = useState(
@@ -115,7 +125,8 @@ function LengthInput({
       return;
     }
     const normalized = Math.min(Math.max(number, 0), maximum);
-    const rounded = Math.round(normalized * 10) / 10;
+    const factor = 10 ** precision;
+    const rounded = Math.round(normalized * factor) / factor;
     setDraft(String(rounded));
     onChange(`${rounded}mm`);
   }
@@ -128,8 +139,9 @@ function LengthInput({
           type="number"
           min="0"
           max={maximum}
-          step="0.1"
+          step={step}
           value={draft}
+          disabled={disabled}
           onBlur={commit}
           onChange={(event) => setDraft(event.target.value)}
           onKeyDown={(event) => {
@@ -144,6 +156,57 @@ function LengthInput({
   );
 }
 
+function PageDecorationFontInput({
+  label,
+  value,
+  disabled,
+  onChange
+}: {
+  label: string;
+  value: string;
+  disabled: boolean;
+  onChange: (value: string) => void;
+}) {
+  const [draft, setDraft] = useState(value);
+
+  useEffect(() => {
+    setDraft(value);
+  }, [value]);
+
+  function commit() {
+    const normalized = draft.trim();
+    if (
+      !normalized ||
+      !/^[\p{L}\p{N}\s,"'-]+$/u.test(normalized)
+    ) {
+      setDraft(value);
+      return;
+    }
+    setDraft(normalized);
+    onChange(normalized);
+  }
+
+  return (
+    <label className="setting-field stacked">
+      <span>{label}</span>
+      <input
+        type="text"
+        maxLength={300}
+        value={draft}
+        disabled={disabled}
+        placeholder='"Segoe UI", "Microsoft YaHei", sans-serif'
+        onBlur={commit}
+        onChange={(event) => setDraft(event.target.value)}
+        onKeyDown={(event) => {
+          if (event.key === "Enter") {
+            event.currentTarget.blur();
+          }
+        }}
+      />
+    </label>
+  );
+}
+
 function MermaidFontInput({
   value,
   onChange
@@ -208,6 +271,7 @@ function updateHeaderSlot(
 
 export function ExportSettingsDrawer({
   config,
+  theme,
   onChange,
   onClose,
   onReset
@@ -259,6 +323,7 @@ export function ExportSettingsDrawer({
     value: string
   ) {
     updatePaper({
+      marginMode: "custom",
       margins: {
         ...margins,
         [side]: value
@@ -266,9 +331,22 @@ export function ExportSettingsDrawer({
     });
   }
 
+  function followThemeMargins() {
+    updatePaper({
+      marginMode: "theme",
+      margins: theme?.pageDefaults?.margins ?? {
+        top: "16mm",
+        right: "16mm",
+        bottom: "16mm",
+        left: "16mm"
+      }
+    });
+  }
+
   function updateHeader(header: Partial<HeaderConfig>) {
     onChange({
       ...config,
+      pageDecorationsMode: "custom",
       header: {
         ...config.header,
         ...header
@@ -279,6 +357,7 @@ export function ExportSettingsDrawer({
   function updateFooter(footer: Partial<FooterConfig>) {
     onChange({
       ...config,
+      pageDecorationsMode: "custom",
       footer: {
         ...config.footer,
         ...footer
@@ -286,6 +365,19 @@ export function ExportSettingsDrawer({
     });
   }
 
+  function followThemePageDecorations() {
+    onChange({
+      ...config,
+      pageDecorationsMode: "theme",
+      header: structuredClone(
+        theme?.pageDefaults?.header ?? defaultExportConfig.header
+      ),
+      footer: structuredClone(
+        theme?.pageDefaults?.footer ?? defaultExportConfig.footer
+      )
+    });
+  }
+
   function updateMermaid(mermaid: Partial<MermaidExportConfig>) {
     onChange({
       ...config,
@@ -374,6 +466,34 @@ export function ExportSettingsDrawer({
 
           <section className="settings-section">
             <h3>页边距</h3>
+            <fieldset className="segmented-control margin-mode-control">
+              <legend>页边距来源</legend>
+              <label>
+                <input
+                  type="radio"
+                  name="margin-mode"
+                  checked={config.paper.marginMode === "theme"}
+                  onChange={followThemeMargins}
+                />
+                跟随主题
+              </label>
+              <label>
+                <input
+                  type="radio"
+                  name="margin-mode"
+                  checked={config.paper.marginMode === "custom"}
+                  onChange={() => updatePaper({ marginMode: "custom" })}
+                />
+                自定义
+              </label>
+            </fieldset>
+            <p className="setting-hint margin-source-hint">
+              {config.paper.marginMode === "theme"
+                ? theme?.pageDefaults
+                  ? `当前采用“${theme.name}”推荐值`
+                  : "当前主题未设置推荐值，采用全局默认 16mm"
+                : "当前采用自定义值；修改任意页边距会自动进入此模式"}
+            </p>
             <div className="margin-grid">
               <LengthInput
                 label="上"
@@ -416,6 +536,15 @@ export function ExportSettingsDrawer({
                 onChange={(value) => updateMargin("left", value)}
               />
             </div>
+            {config.paper.marginMode === "custom" ? (
+              <button
+                type="button"
+                className="secondary-action margin-reset-action"
+                onClick={followThemeMargins}
+              >
+                恢复主题推荐值
+              </button>
+            ) : null}
           </section>
 
           <section className="settings-section">
@@ -485,6 +614,53 @@ export function ExportSettingsDrawer({
             </p>
           </section>
 
+          <section className="settings-section">
+            <h3>页眉与页码来源</h3>
+            <fieldset className="segmented-control margin-mode-control">
+              <legend>页面装饰来源</legend>
+              <label>
+                <input
+                  type="radio"
+                  name="page-decorations-mode"
+                  checked={config.pageDecorationsMode === "theme"}
+                  onChange={followThemePageDecorations}
+                />
+                跟随主题
+              </label>
+              <label>
+                <input
+                  type="radio"
+                  name="page-decorations-mode"
+                  checked={config.pageDecorationsMode === "custom"}
+                  onChange={() =>
+                    onChange({
+                      ...config,
+                      pageDecorationsMode: "custom"
+                    })
+                  }
+                />
+                自定义
+              </label>
+            </fieldset>
+            <p className="setting-hint margin-source-hint">
+              {config.pageDecorationsMode === "theme"
+                ? theme?.pageDefaults?.header ||
+                  theme?.pageDefaults?.footer
+                  ? `当前采用“${theme.name}”推荐的页眉与页码`
+                  : "当前主题未设置推荐值，采用全局默认配置"
+                : "当前采用自定义配置；修改页眉或页码会自动进入此模式"}
+            </p>
+            {config.pageDecorationsMode === "custom" ? (
+              <button
+                type="button"
+                className="secondary-action margin-reset-action"
+                onClick={followThemePageDecorations}
+              >
+                恢复主题推荐值
+              </button>
+            ) : null}
+          </section>
+
           <section className="settings-section">
             <div className="setting-section-title">
               <h3>页眉</h3>
@@ -502,6 +678,21 @@ export function ExportSettingsDrawer({
             <p className="setting-hint">
               支持 {"${title}"}、{"${author}"} 和 {"${filename}"}。
             </p>
+            <PageDecorationFontInput
+              label="页眉字体"
+              value={config.header.fontFamily}
+              disabled={!config.header.enabled}
+              onChange={(fontFamily) => updateHeader({ fontFamily })}
+            />
+            <LengthInput
+              label="页眉字号"
+              value={config.header.fontSize}
+              maximum={20}
+              disabled={!config.header.enabled}
+              precision={2}
+              step={0.01}
+              onChange={(fontSize) => updateHeader({ fontSize })}
+            />
             {(["left", "center", "right"] as const).map((slot) => {
               const labels = { left: "左侧", center: "中间", right: "右侧" };
               return (
@@ -567,6 +758,21 @@ export function ExportSettingsDrawer({
                 <span>{config.footer.enabled ? "开启" : "关闭"}</span>
               </label>
             </div>
+            <PageDecorationFontInput
+              label="页码字体"
+              value={config.footer.fontFamily}
+              disabled={!config.footer.enabled}
+              onChange={(fontFamily) => updateFooter({ fontFamily })}
+            />
+            <LengthInput
+              label="页码字号"
+              value={config.footer.fontSize}
+              maximum={20}
+              disabled={!config.footer.enabled}
+              precision={2}
+              step={0.01}
+              onChange={(fontSize) => updateFooter({ fontSize })}
+            />
             <label className="setting-field">
               <span>样式</span>
               <select
@@ -616,6 +822,7 @@ export function ExportSettingsDrawer({
                 <option value="left">左侧</option>
                 <option value="center">居中</option>
                 <option value="right">右侧</option>
+                <option value="outer">外侧（奇数页右、偶数页左）</option>
               </select>
             </label>
             <label className="setting-field">
@@ -636,6 +843,19 @@ export function ExportSettingsDrawer({
                 }
               />
             </label>
+            <label className="switch-control divider-control">
+              <input
+                type="checkbox"
+                checked={config.footer.showOnFirstPage}
+                disabled={!config.footer.enabled}
+                onChange={(event) =>
+                  updateFooter({
+                    showOnFirstPage: event.target.checked
+                  })
+                }
+              />
+              <span>首页显示页码</span>
+            </label>
             <label className="switch-control divider-control">
               <input
                 type="checkbox"