feat: 增加 ECharts 渲染与预览交互增强

- 新增可复用的 markdown-echarts 工作区，支持安全的 YAML 围栏、默认值、语义校验、错误占位和 SVG 渲染
- 将 ECharts 接入统一 Markdown、快速预览、精确预览与 PDF 链路，并复用 Mermaid 的不可跨页和超高图单页适配策略
- 默认示例加入 ECharts，增加源文本折叠、顶部文档状态、页码输入跳转与滚动同步
- 快速预览改用外层容器滚动，使滚动条与精确预览统一贴在预览区域右侧，并兼容显示缩放
- 完善 Docker 工作区复制、可配置 Compose 镜像、测试覆盖和进度文档

apps/web/src/paged-preview.ts

@@ -4,8 +4,6 @@ import {
   type MarkdownDocumentMetadata,
   type PagedDocumentPayload
 } from "@md-to-pdf/core";
-import { PREVIEW_SCROLLBAR_WIDTH_PX } from "./preview-page";
-
 export const PAGED_PREVIEW_MESSAGE_SCOPE = "md-to-pdf:paged-preview";
 
 export type PreviewMetadata = MarkdownDocumentMetadata;
@@ -33,6 +31,8 @@ export type PagedPreviewFrameMessage =
       type: "rendered";
       requestId: number;
       pageCount: number;
+      contentHeight: number;
+      echartsErrors: string[];
       mermaidErrors: string[];
     }
   | {
@@ -92,6 +92,11 @@ svg {
   background: #fef2f2;
   white-space: pre-wrap;
 }
+
+.md-echarts {
+  break-inside: avoid;
+  page-break-inside: avoid;
+}
 `;
 
 export const documentGeometryCss = `
@@ -293,7 +298,8 @@ ${buildFooterCss(config)}
 #write pre,
 #write blockquote,
 #write .katex-display,
-#write .mermaid {
+#write .mermaid,
+#write .md-echarts {
   break-inside: avoid;
 }
 
@@ -329,16 +335,7 @@ ${
 html[data-render-target="preview"] {
   height: 100%;
   overflow-x: hidden;
-  overflow-y: scroll;
-  scrollbar-gutter: stable;
-}
-
-html[data-render-target="preview"]::-webkit-scrollbar {
-  width: ${PREVIEW_SCROLLBAR_WIDTH_PX}px;
-}
-
-html[data-render-target="preview"]::-webkit-scrollbar:horizontal {
-  height: 0;
+  overflow-y: hidden;
 }
 
 html[data-render-target="preview"] body {
@@ -413,10 +410,26 @@ export function isPagedPreviewFrameMessage(
   }
 
   const candidate = value as Partial<PagedPreviewFrameMessage>;
-  return (
-    candidate.scope === PAGED_PREVIEW_MESSAGE_SCOPE &&
-    ["ready", "rendering", "rendered", "error"].includes(
+  if (
+    candidate.scope !== PAGED_PREVIEW_MESSAGE_SCOPE ||
+    !["ready", "rendering", "rendered", "error"].includes(
       candidate.type ?? ""
     )
+  ) {
+    return false;
+  }
+
+  if (candidate.type !== "rendered") {
+    return true;
+  }
+
+  return (
+    Number.isInteger(candidate.requestId) &&
+    Number.isInteger(candidate.pageCount) &&
+    typeof candidate.contentHeight === "number" &&
+    Number.isFinite(candidate.contentHeight) &&
+    candidate.contentHeight > 0 &&
+    Array.isArray(candidate.echartsErrors) &&
+    Array.isArray(candidate.mermaidErrors)
   );
 }