feat: 完善 Mermaid 配置与预览缩放

apps/web/src/export-settings.ts

@@ -4,7 +4,9 @@ import {
   type ExportConfig
 } from "@md-to-pdf/core";
 
-export const EXPORT_CONFIG_STORAGE_KEY = "md-to-pdf.export-config.v2";
+export const EXPORT_CONFIG_STORAGE_KEY = "md-to-pdf.export-config.v3";
+export const LEGACY_EXPORT_CONFIG_STORAGE_KEY =
+  "md-to-pdf.export-config.v2";
 
 type SettingsStorage = Pick<Storage, "getItem" | "setItem">;
 
@@ -18,7 +20,19 @@ export function parseStoredExportConfig(rawValue: string | null): ExportConfig {
   }
 
   try {
-    const parsed = exportConfigSchema.safeParse(JSON.parse(rawValue));
+    const value: unknown = JSON.parse(rawValue);
+    const migratedValue =
+      typeof value === "object" &&
+      value !== null &&
+      "version" in value &&
+      value.version === 2
+        ? {
+            ...value,
+            version: defaultExportConfig.version,
+            mermaid: structuredClone(defaultExportConfig.mermaid)
+          }
+        : value;
+    const parsed = exportConfigSchema.safeParse(migratedValue);
     return parsed.success ? parsed.data : cloneDefaultExportConfig();
   } catch {
     return cloneDefaultExportConfig();
@@ -28,7 +42,17 @@ export function parseStoredExportConfig(rawValue: string | null): ExportConfig {
 export function loadExportConfig(
   storage: SettingsStorage = window.localStorage
 ) {
-  return parseStoredExportConfig(storage.getItem(EXPORT_CONFIG_STORAGE_KEY));
+  const currentValue = storage.getItem(EXPORT_CONFIG_STORAGE_KEY);
+  if (currentValue) {
+    return parseStoredExportConfig(currentValue);
+  }
+
+  const legacyValue = storage.getItem(LEGACY_EXPORT_CONFIG_STORAGE_KEY);
+  const config = parseStoredExportConfig(legacyValue);
+  if (legacyValue) {
+    storage.setItem(EXPORT_CONFIG_STORAGE_KEY, JSON.stringify(config));
+  }
+  return config;
 }
 
 export function saveExportConfig(