🚨 disable export/history/import for encrypted notebooks (stage 7) #18034

Encrypted notebooks bypass filesys for export/history/import, which would
either leak ciphertext (export) or corrupt data (import writes plaintext
.sy into encrypted dir). Disable these three features for encrypted boxes
until proper integration is built.

- model/export.go: ExportNotebookSY and ExportSYs return early for
  encrypted boxes
- model/history.go: GenerateFileHistory skips encrypted boxes in the
  ticker loop; generateTreeHistory returns early for encrypted trees
  (covers both auto and edit-triggered history)
- model/import.go: ImportSY and ImportFromLocalPath return error for
  encrypted target boxes

Sync (.sy/assets) is NOT changed: the sync loop is naturally correct —
files are ciphertext on disk, dejavu reads ciphertext and uploads
ciphertext, checkout writes ciphertext back. DEK encryption is preserved
end-to-end without intervention.

#18034

Author: 88250

kernel/model/export.go

@@ -500,12 +500,20 @@ func ExportSystemLog() (zipPath string) {
 }
 
 func ExportNotebookSY(id string) (zipPath string) {
+	// 加密笔记本不支持导出，避免密文 .sy 流出后无法解读
+	if IsEncryptedBox(id) {
+		return
+	}
 	zipPath = exportBoxSYZip(id)
 	return
 }
 
 func ExportSYs(ids []string) (zipPath string) {
 	block := treenode.GetBlockTree(ids[0])
+	// 加密笔记本不支持导出
+	if nil != block && IsEncryptedBox(block.BoxID) {
+		return
+	}
 	box := Conf.Box(block.BoxID)
 	baseFolderName := path.Base(block.HPath)
 	if "." == baseFolderName {

kernel/model/history.go

@@ -70,6 +70,10 @@ func GenerateFileHistory() {
 
 	// 生成文档历史
 	for _, box := range Conf.GetOpenedBoxes() {
+		// 加密笔记本不生成历史（历史目录不加密，密文 .sy 写进去也无意义）
+		if IsEncryptedBox(box.ID) {
+			continue
+		}
 		box.generateDocHistory0()
 	}
 
@@ -857,6 +861,10 @@ func CreateDocHistory(id string) (err error) {
 }
 
 func generateTreeHistory(tree *parse.Tree, historyDir string) {
+	// 加密笔记本不生成历史
+	if IsEncryptedBox(tree.Box) {
+		return
+	}
 	historyPath := filepath.Join(historyDir, tree.Box, tree.Path)
 	var err error
 	if err = os.MkdirAll(filepath.Dir(historyPath), 0755); err != nil {

kernel/model/import.go

@@ -108,6 +108,11 @@ func HTML2Tree(htmlStr string, luteEngine *lute.Lute) (tree *parse.Tree, withMat
 }
 
 func ImportSY(zipPath, boxID, toPath string) (err error) {
+	// 加密笔记本不支持导入（导入的 .sy 是明文，落到加密目录会导致读取失败）
+	if IsEncryptedBox(boxID) {
+		err = errors.New("import to encrypted notebook is not supported")
+		return
+	}
 	util.PushEndlessProgress(Conf.Language(73))
 	defer util.ClearPushProgress(100)
 
@@ -769,6 +774,11 @@ func ImportData(zipPath string) (err error) {
 }
 
 func ImportFromLocalPath(boxID, localPath string, toPath string) (err error) {
+	// 加密笔记本不支持导入
+	if IsEncryptedBox(boxID) {
+		err = errors.New("import to encrypted notebook is not supported")
+		return
+	}
 	util.PushEndlessProgress(Conf.Language(73))
 	defer func() {
 		util.PushClearProgress()