feat: 完善 Mermaid 配置与预览缩放

apps/web/src/paged-preview-frame.ts

@@ -7,6 +7,10 @@ import {
 } from "./paged-preview";
 import { resolvePagedRenderTarget } from "./paged-render-target";
 import { resolveMermaidOutputMode } from "./mermaid-static-image";
+import {
+  beginPreviewFrameRender,
+  completePreviewFrameRender
+} from "./preview-frame-visibility";
 
 function getPreviewRoot() {
   const element = document.querySelector<HTMLElement>("#preview-root");
@@ -37,27 +41,34 @@ async function renderPagedPreview(
     return;
   }
 
+  beginPreviewFrameRender(document.documentElement, requestId);
   post({
     scope: PAGED_PREVIEW_MESSAGE_SCOPE,
     type: "rendering",
     requestId
   });
 
-  const result = await runtime.render(payload, {
-    target: renderTarget,
-    mermaidOutput,
-    shouldContinue: () => requestId === latestRequestId
-  });
-  if (!result) {
-    return;
-  }
+  try {
+    const result = await runtime.render(payload, {
+      target: renderTarget,
+      mermaidOutput,
+      shouldContinue: () => requestId === latestRequestId
+    });
+    if (!result) {
+      return;
+    }
 
-  post({
-    scope: PAGED_PREVIEW_MESSAGE_SCOPE,
-    type: "rendered",
-    requestId,
-    ...result
-  });
+    post({
+      scope: PAGED_PREVIEW_MESSAGE_SCOPE,
+      type: "rendered",
+      requestId,
+      ...result
+    });
+  } finally {
+    if (requestId === latestRequestId) {
+      completePreviewFrameRender(document.documentElement, requestId);
+    }
+  }
 }
 
 window.__mdToPdfRender = async (