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。

packages/application/tests/application-service.test.ts

@@ -37,7 +37,13 @@ async function createThemeFixture() {
   const bundledRoot = join(temporaryDirectory, "bundled");
   const localRoot = join(temporaryDirectory, "local");
   const themeRoot = join(bundledRoot, "test-theme");
+  const sharedFontRoot = join(
+    bundledRoot,
+    "_shared",
+    "official-fonts"
+  );
   await mkdir(join(themeRoot, "fonts"), { recursive: true });
+  await mkdir(sharedFontRoot, { recursive: true });
   await mkdir(localRoot, { recursive: true });
   await writeFile(
     join(themeRoot, "theme.json"),
@@ -53,6 +59,14 @@ async function createThemeFixture() {
       domPreset: "typora",
       defaultFontSize: "16px",
       supportedFeatures: ["code", "table"],
+      pageDefaults: {
+        margins: {
+          top: "37mm",
+          right: "26mm",
+          bottom: "35mm",
+          left: "28mm"
+        }
+      },
       bundled: true
     }),
     "utf8"
@@ -64,6 +78,10 @@ async function createThemeFixture() {
       "  font-family: Test;",
       "  src: url('./fonts/test.woff2') format('woff2');",
       "}",
+      "@font-face {",
+      "  font-family: SharedTest;",
+      "  src: url('theme-shared:official-fonts/shared.woff2') format('woff2');",
+      "}",
       "#write { font-family: Test; }"
     ].join("\n"),
     "utf8"
@@ -72,6 +90,10 @@ async function createThemeFixture() {
     join(themeRoot, "fonts", "test.woff2"),
     Buffer.from([0, 1, 2, 3])
   );
+  await writeFile(
+    join(sharedFontRoot, "shared.woff2"),
+    Buffer.from([4, 5, 6, 7])
+  );
   return { bundledRoot, localRoot };
 }
 
@@ -147,6 +169,16 @@ describe("共享应用服务", () => {
       themes: [
         expect.objectContaining({
           id: "test-theme",
+          category: "general",
+          compatibleProfiles: [],
+          pageDefaults: {
+            margins: {
+              top: "37mm",
+              right: "26mm",
+              bottom: "35mm",
+              left: "28mm"
+            }
+          },
           bundled: true,
           source: "bundled"
         })
@@ -157,6 +189,11 @@ describe("共享应用服务", () => {
     ).resolves.toContain(
       "mdpdf://theme/test-theme/fonts/test.woff2"
     );
+    await expect(
+      service.getThemeCss("test-theme")
+    ).resolves.toContain(
+      "mdpdf://theme/_shared/official-fonts/shared.woff2"
+    );
   });
 
   it("安全读取主题二进制资源", async () => {
@@ -172,6 +209,18 @@ describe("共享应用服务", () => {
     await expect(
       service.getThemeAsset("test-theme", "../test.woff2")
     ).rejects.toThrow("主题资源路径不安全");
+    await expect(
+      service.getThemeAsset(
+        "_shared",
+        "official-fonts/shared.woff2"
+      )
+    ).resolves.toEqual({
+      contentType: "font/woff2",
+      content: Buffer.from([4, 5, 6, 7])
+    });
+    await expect(
+      service.getThemeAsset("_shared", "../shared.woff2")
+    ).rejects.toThrow("主题资源路径不安全");
   });
 
   it("内置主题优先于同 ID 的旧本地副本", async () => {