feat: 完成 DOCX R4 元素级视觉门禁

建立 Chromium、Word 与 WPS 的可编辑内容、段落几何、页眉页脚、封面、媒体和逐页视觉比较链路。

支持封面独立分节、正文页码重启、主题页边距与横向纸张，并将自然分页差异降为诊断项。

修正代码块内边距和折叠表格单元格边框映射，14 套主题生产矩阵与六组布局视觉矩阵通过。

packages/semantic-document/src/model-builder.ts

@@ -41,7 +41,8 @@ function text(
 
 function group(
   role: SemanticDocumentRole,
-  children: readonly (SemanticDocumentNode | undefined)[]
+  children: readonly (SemanticDocumentNode | undefined)[],
+  layout?: SemanticDocumentGroupNode["layout"]
 ): SemanticDocumentGroupNode | undefined {
   const resolved = children.filter(
     (child): child is SemanticDocumentNode => child !== undefined
@@ -50,6 +51,7 @@ function group(
     ? {
         kind: "group",
         role,
+        ...(layout ? { layout } : {}),
         children: resolved
       }
     : undefined;
@@ -89,11 +91,11 @@ function officialRegions(
   const classification = group("official-classification", [
     text("official-secrecy", document.secrecy),
     text("official-urgency", document.urgency)
-  ]);
+  ], "space-between");
   const issueRow = group("official-issue-row", [
     text("official-number", document.number),
     text("official-signatory", document.signatory, "签发人：")
-  ]);
+  ], "space-between");
   const masthead = group("official-masthead", [
     classification,
     text("official-issuer", document.issuer),
@@ -109,7 +111,7 @@ function officialRegions(
       "official-printing-date",
       document.date ? `${document.date}印发` : undefined
     )
-  ]);
+  ], "space-between");
   const edition = group("official-edition", [
     text(
       "official-copy-to",
@@ -138,7 +140,7 @@ function briefingRegions(
     text("briefing-publisher", document.publisher),
     text("briefing-signatory", document.signatory, "签发："),
     text("briefing-date", document.date)
-  ]);
+  ], "space-between");
   const masthead = group("briefing-masthead", [
     text("briefing-masthead-text", document.masthead),
     details

packages/semantic-document/tests/model-builder.test.ts

@@ -57,6 +57,9 @@ describe("统一语义文档模型", () => {
       "suffix"
     ]);
     expect(JSON.stringify(model)).toContain("official-masthead");
+    expect(JSON.stringify(model)).toContain(
+      '"layout":"space-between"'
+    );
     expect(JSON.stringify(model)).toContain("抄送：");
     expect(JSON.stringify(model)).toContain("2026年7月30日印发");
     expect(() => semanticDocumentModelSchema.parse(model))