fix: 修复 markdown 编辑保存后内容丢失的问题

- 在 saveContent 中缓存 unsavedContent，避免 async 期间的竞态条件
- 在 useMarkdownLogic 中添加 lastContentRef 跟踪内容变化，防止不必要的编辑器更新

src/hooks/domain/useMarkdownLogic.ts

@@ -85,6 +85,8 @@ export const useMarkdownLogic = ({
   const readOnlyRef = useRef(readOnly)
   const ctxRef = useRef<Ctx | null>(null)
 
+  const lastContentRef = useRef<string>('')
+
   useEffect(() => {
     onChangeRef.current = onChange
   }, [])
@@ -117,23 +119,28 @@ export const useMarkdownLogic = ({
     }
   }, [readOnly])
 
-  // 在只读模式下动态更新内容
+  // 在只读模式下动态更新内容（仅当 content 真正变化时）
   useEffect(() => {
     if (!ctxRef.current || !readOnly) return
+    
+    // 只有当 content 真正变化时才更新编辑器
+    if (content === lastContentRef.current) return
+    lastContentRef.current = content
+
     try {
       const view = ctxRef.current.get(editorViewCtx)
       const parser = ctxRef.current.get(parserCtx)
       const doc = parser(content)
       if (!doc) return
 
-      const state = view.state
-      view.dispatch(state.tr.replaceWith(0, state.doc.content.size, doc))
+      view.dispatch(view.state.tr.replaceWith(0, view.state.doc.content.size, doc))
     } catch {
       // 编辑器可能尚未就绪
     }
   }, [content, readOnly])
 
   return useEditor((root) => {
+    lastContentRef.current = content
     return Editor.make()
       .config((ctx) => {
         ctxRef.current = ctx

src/stores/tabStore.ts

@@ -331,7 +331,9 @@ export const useTabStore = create<TabStore>((set, get) => {
       const isAsyncImportProcessing = isAsyncImportProcessingContent(tab.content)
       if (isAsyncImportProcessing) return
 
-      await saveFileContent(filePath, tab.unsavedContent)
+      const contentToSave = tab.unsavedContent
+
+      await saveFileContent(filePath, contentToSave)
 
       set((state) => {
         const newTabs = new Map(state.tabs)
@@ -339,7 +341,8 @@ export const useTabStore = create<TabStore>((set, get) => {
         if (currentTab) {
           newTabs.set(filePath, {
             ...currentTab,
-            content: currentTab.unsavedContent,
+            content: contentToSave,
+            unsavedContent: contentToSave,
             isEditing: false,
           })
         }