fix: select RXTX channel by firmware family

tests/test_protocol.py

@@ -61,6 +61,12 @@ class TestSetTime:
 
 
 class TestCommandFrames:
+    def test_rxtx_channel_by_firmware_family(self):
+        assert P.select_rxtx_uuid("HM42_AIO_V1.0.9") == P.RXTX_CHAR_UUID_LEGACY
+        assert P.select_rxtx_uuid("hm42_aio_v2") == P.RXTX_CHAR_UUID_LEGACY
+        assert P.select_rxtx_uuid("PP_da14585_4.2") == P.RXTX_CHAR_UUID
+        assert P.select_rxtx_uuid(None) == P.RXTX_CHAR_UUID
+
     def test_parking(self):
         """停车牌 "12" → EF1122（向量#4）"""
         assert P.parking_frame("12") == bytes([0xEF, 0x11, 0x22])