feat: sync keyboard led status (#502)

usb.go

@@ -24,6 +24,17 @@ func initUsbGadget() {
 			time.Sleep(500 * time.Millisecond)
 		}
 	}()
+
+	gadget.SetOnKeyboardStateChange(func(state usbgadget.KeyboardState) {
+		if currentSession != nil {
+			writeJSONRPCEvent("keyboardLedState", state, currentSession)
+		}
+	})
+
+	// open the keyboard hid file to listen for keyboard events
+	if err := gadget.OpenKeyboardHidFile(); err != nil {
+		usbLogger.Error().Err(err).Msg("failed to open keyboard hid file")
+	}
 }
 
 func rpcKeyboardReport(modifier uint8, keys []uint8) error {
@@ -42,6 +53,10 @@ func rpcWheelReport(wheelY int8) error {
 	return gadget.AbsMouseWheelReport(wheelY)
 }
 
+func rpcGetKeyboardLedState() (state usbgadget.KeyboardState) {
+	return gadget.GetKeyboardState()
+}
+
 var usbState = "unknown"
 
 func rpcGetUSBState() (state string) {