feat: add file transfer support (#55)

* feat: add file transfer support

* 1MB buffer

model/task.go

@@ -12,6 +12,7 @@ const (
 	TaskTypeTerminalGRPC
 	TaskTypeNAT
 	TaskTypeReportHostInfo
+	TaskTypeFM
 )
 
 type TerminalTask struct {
@@ -22,3 +23,7 @@ type TaskNAT struct {
 	StreamID string
 	Host     string
 }
+
+type TaskFM struct {
+	StreamID string
+}