feat: LoRa频率设定范围改为433.1~492.6MHz, 步进500KHz

- sx127x.h: CH0~CH45宏表(470.1~492.6MHz, 46信道)替换为算术定义:
  LORA_FREQ_BASE=433100000, LORA_FREQ_STEP=500000, LORA_FREQ_MAX=492600000,
  LORA_CHANNEL_CNT=120(CH0~CH119); FREQ_CENT由编译期USE_LORA_CH(0~119)算术换算,
  未指定时出厂默认CH0=433.1MHz
- sx127x.c: LoraSetFreqCent范围校验放宽至433.1~492.6MHz; LoraSetChannel上限45->119
- main.c: Flash参数BLPara.LoraFreq范围校验同步放宽至433.1~492.6MHz
- 频率公式: Freq = 433100000 + 500000*N, N = 0~119
- 新旧信道号映射: 旧CHn = 新CH(74+n), 例: 旧CH0(470.1MHz) = 新CH74
- 注意: 网关侧需使用相同频率集合
- 所有编辑文件保持UTF-8编码(无BOM)

source/src/main.c

@@ -137,10 +137,10 @@ static void AppInit(void)
     App.Para.Layout.FPOTimeStart = 0;
 	}
 	
-	if(App.Para.BLPara.LoraFreq < 470100000ul || App.Para.BLPara.LoraFreq > 492600000ul)
+	if(App.Para.BLPara.LoraFreq < LORA_FREQ_BASE || App.Para.BLPara.LoraFreq > LORA_FREQ_MAX)		//宽带: 433.1~492.6MHz
 		App.Para.BLPara.LoraFreq = CH0;
 	App.Para.Lora.FreqCent = App.Para.BLPara.LoraFreq;
-	SX1276LoRaWriteFreq(App.Para.Lora.FreqCent);		//Lora频率:470100000ul + 500000*N
+	SX1276LoRaWriteFreq(App.Para.Lora.FreqCent);		//Lora频率:433100000ul + 500000*N, 范围433.1~492.6MHz
 	
 	if(App.Para.Rs485Ch1.Addr > 16 || App.Para.Rs485Ch1.Addr < 1){
 		App.Para.Rs485Ch1.Addr = 1;