v1.8.0: Audio 代码重构与低功耗优化 (#943)

* Reconstruct Audio Code

* Remove old IoT implementation

* Add MQTT-UDP documentation

* OTA升级失败时，可以继续使用

main/boards/common/adc_battery_monitor.h

@@ -0,0 +1,30 @@
+#ifndef ADC_BATTERY_MONITOR_H
+#define ADC_BATTERY_MONITOR_H
+
+#include <functional>
+#include <driver/gpio.h>
+#include <adc_battery_estimation.h>
+#include <esp_timer.h>
+
+class AdcBatteryMonitor {
+public:
+    AdcBatteryMonitor(adc_unit_t adc_unit, adc_channel_t adc_channel, float upper_resistor, float lower_resistor, gpio_num_t charging_pin = GPIO_NUM_NC);
+    ~AdcBatteryMonitor();
+
+    bool IsCharging();
+    bool IsDischarging();
+    uint8_t GetBatteryLevel();
+
+    void OnChargingStatusChanged(std::function<void(bool)> callback);
+
+private:
+    gpio_num_t charging_pin_;
+    adc_battery_estimation_handle_t adc_battery_estimation_handle_ = nullptr;
+    esp_timer_handle_t timer_handle_ = nullptr;
+    bool is_charging_ = false;
+    std::function<void(bool)> on_charging_status_changed_;
+
+    void CheckBatteryStatus();
+};
+
+#endif // ADC_BATTERY_MONITOR_H