fix(ws): add NoteDeleteAck and FileDeleteAck to prevent hash orphan on disconnect

Previously, noteDelete/fileDelete removed hash from hashManager in the on-send
callback (when message entered TCP buffer), before server confirmation. If TCP
dropped between send and server receipt, the hash was permanently gone — on
reconnect, the path skipped delNotes and the server file became a permanent orphan.

Introduce NoteDeleteAck/FileDeleteAck responses (symmetric with existing
NoteModifyAck/NoteRenameAck pattern): server sends Ack with lastTime and path
after processing the delete. Client defers hash removal to Ack receipt; on
reconnect, unconfirmed paths remain in hashManager and flow into delNotes naturally.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: chenxiccc

internal/dto/file_dto_ws.go

@@ -75,6 +75,13 @@ type FileUploadAckMessage struct {
 	Path     string `json:"path"`     // File path // 文件路径
 }
 
+// FileDeleteAckMessage file delete operation ACK, sent back to sender after server processes FileDelete
+// FileDeleteAckMessage 文件删除操作 ACK，服务端处理完 FileDelete 后回发给发送方
+type FileDeleteAckMessage struct {
+	LastTime int64  `json:"lastTime"` // Server write timestamp // 服务端写入时间戳
+	Path     string `json:"path"`     // File path // 文件路径
+}
+
 // FileSyncRenameMessage message structure for file rename during sync
 // FileSyncRenameMessage 同步过程中文件重命名的消息结构
 type FileSyncRenameMessage struct {

internal/dto/note_dto_ws.go

@@ -75,3 +75,10 @@ type NoteModifyAckMessage struct {
 type NoteRenameAckMessage struct {
 	LastTime int64 `json:"lastTime"` // Server write timestamp // 服务端写入时间戳
 }
+
+// NoteDeleteAckMessage note delete operation ACK, sent back to sender after server processes NoteDelete
+// NoteDeleteAckMessage 笔记删除操作 ACK，服务端处理完 NoteDelete 后回发给发送方
+type NoteDeleteAckMessage struct {
+	LastTime int64  `json:"lastTime"` // Server write timestamp // 服务端写入时间戳
+	Path     string `json:"path"`     // Note path // 笔记路径
+}

internal/dto/ws_dto.go

@@ -136,6 +136,9 @@ const (
 	// NoteRenameAck note rename operation ack
 	// NoteRenameAck 笔记重命名操作 ack
 	NoteRenameAck WebSocketSendAction = "NoteRenameAck"
+	// NoteDeleteAck note delete operation ack
+	// NoteDeleteAck 笔记删除操作 ack
+	NoteDeleteAck WebSocketSendAction = "NoteDeleteAck"
 
 	// ---------------- File ----------------
 
@@ -166,6 +169,9 @@ const (
 	// FileUploadAck file upload complete ack
 	// FileUploadAck 文件上传完成 ack
 	FileUploadAck WebSocketSendAction = "FileUploadAck"
+	// FileDeleteAck file delete operation ack
+	// FileDeleteAck 文件删除操作 ack
+	FileDeleteAck WebSocketSendAction = "FileDeleteAck"
 
 	// ---------------- Setting ----------------
 

internal/routers/websocket_router/ws_file.go

@@ -412,7 +412,10 @@ func (h *FileWSHandler) FileDelete(c *pkgapp.WebsocketClient, msg *pkgapp.WebSoc
 		return
 	}
 
-	c.ToResponse(code.Success)
+	c.ToResponse(code.Success.WithData(dto.FileDeleteAckMessage{
+		LastTime: fileSvc.UpdatedTimestamp,
+		Path:     fileSvc.Path,
+	}).WithVault(params.Vault), string(dto.FileDeleteAck))
 
 	// Broadcast file deletion message
 	// 广播文件删除消息

internal/routers/websocket_router/ws_note.go

@@ -524,7 +524,10 @@ func (h *NoteWSHandler) NoteDelete(c *pkgapp.WebsocketClient, msg *pkgapp.WebSoc
 		return
 	}
 
-	c.ToResponse(code.Success)
+	c.ToResponse(code.Success.WithData(dto.NoteDeleteAckMessage{
+		LastTime: note.UpdatedTimestamp,
+		Path:     note.Path,
+	}).WithVault(params.Vault), string(dto.NoteDeleteAck))
 	c.BroadcastResponse(code.Success.WithData(
 		dto.NoteSyncDeleteMessage{
 			Path:             note.Path,