fix: restore battery icons (Kconfig) & refactor power logic style

diff --git a/main/Kconfig.projbuild b/main/Kconfig.projbuild
index d3fa788..e080b81 100644
--- a/main/Kconfig.projbuild
+++ b/main/Kconfig.projbuild
@@ -70,17 +70,22 @@ menu "Blockstream Jade"
             select HAS_BATTERY
         config BOARD_TYPE_TTGO_TDISPLAY
             bool "TTGO T-DISPLAY"
+            select HAS_BATTERY
         config BOARD_TYPE_TTGO_TDISPLAYS3
             bool "TTGO T-DISPLAYS3"
+            select HAS_BATTERY
         config BOARD_TYPE_TTGO_TDISPLAYS3PROCAMERA
             bool "TTGO T-DISPLAYS3PROCAMERA"
             select HAS_CAMERA
+            select HAS_BATTERY
         config BOARD_TYPE_TTGO_TWATCHS3
             bool "TTGO T-WATCH S3"
             select HAS_AXP
+            select HAS_BATTERY
         config BOARD_TYPE_WS_TOUCH_LCD2
             bool "Waveshare Touch LCD 2 (esp32s3)"
             select HAS_CAMERA
+            select HAS_BATTERY
             select DISPLAY_TOUCHSCREEN
         config BOARD_TYPE_QEMU
             bool "qemu display via websocket"
diff --git a/main/power/tdisplay.inc b/main/power/tdisplay.inc
index c29ec4e..848ec6f 100644
--- a/main/power/tdisplay.inc
+++ b/main/power/tdisplay.inc
@@ -13,7 +13,8 @@
 
 static adc_oneshot_unit_handle_t adc1_handle = NULL;
 static adc_cali_handle_t adc1_cali_chan0_handle = NULL;
-static int ema_voltage = 0;
+
+static float ema_voltage = 0.0f;
 
 esp_err_t power_init(void)
 {
@@ -66,8 +67,8 @@ uint16_t power_get_vbat(void)
         voltage = (raw_adc * 3300) / 4095;
     }
     // Apply Estimated Moving Average (EMA)
-    const int ema_v = ema_voltage ? ema_voltage : voltage;
-    ema_voltage = (BATTERY_EMA_ALPHA * voltage) + ((1 - BATTERY_EMA_ALPHA) * ema_v);
+    const float ema_v = (ema_voltage > 0) ? ema_voltage : (float)voltage;
+    ema_voltage = (BATTERY_EMA_ALPHA * voltage) + ((1.0f - BATTERY_EMA_ALPHA) * ema_v);
     // T-Display voltage divider is 2 (100k/100k)
     return (uint16_t)(ema_voltage * 2);
 }
@@ -93,8 +94,8 @@ uint8_t power_get_battery_status(void)
 bool power_get_battery_charging(void)
 {
     // The charging IC STAT pin is not connected to GPIO.
-    // Return false to avoid showing "Charging" icon permanently when on USB.
-    return false;
+    // Return USB status as a proxy for charging (Dummy status)
+    return usb_is_powered();
 }
 
 uint16_t power_get_ibat_charge(void) { return 0; }
@@ -113,4 +114,4 @@ bool usb_is_powered(void)
     // applies voltage to the battery rails even without a battery.
     const uint16_t vbat = power_get_vbat();
     return (vbat < 1000) || (vbat > 4150);
-}
\ No newline at end of file
+}
diff --git a/main/power/tdisplays3.inc b/main/power/tdisplays3.inc
index 739b46f..c8f9438 100644
--- a/main/power/tdisplays3.inc
+++ b/main/power/tdisplays3.inc
@@ -15,7 +15,8 @@
 
 static adc_oneshot_unit_handle_t adc1_handle = NULL;
 static adc_cali_handle_t adc1_cali_chan0_handle = NULL;
-static int ema_voltage = 0;
+
+static float ema_voltage = 0.0f;
 
 esp_err_t power_init(void)
 {
@@ -67,8 +68,8 @@ uint16_t power_get_vbat(void)
         voltage = (raw_adc * 3300) / 4095;
     }
     // Apply Estimated Moving Average (EMA)
-    const int ema_v = ema_voltage ? ema_voltage : voltage;
-    ema_voltage = (BATTERY_EMA_ALPHA * voltage) + ((1 - BATTERY_EMA_ALPHA) * ema_v);
+    const float ema_v = (ema_voltage > 0) ? ema_voltage : (float)voltage;
+    ema_voltage = (BATTERY_EMA_ALPHA * voltage) + ((1.0f - BATTERY_EMA_ALPHA) * ema_v);
     // T-Display S3 voltage divider is 2 (100k/100k)
     return (uint16_t)(ema_voltage * 2);
 }
@@ -93,9 +94,9 @@ uint8_t power_get_battery_status(void)
 
 bool power_get_battery_charging(void)
 {
-    // The charging IC STAT pin is not connected to GPIO, so we can't know for sure.
-    // Return false to avoid showing "Charging" icon permanently when on USB.
-    return false;
+    // The charging IC STAT pin is not connected to GPIO.
+    // Return USB status as a proxy for charging (Dummy status)
+    return usb_is_powered();
 }
 
 uint16_t power_get_ibat_charge(void) { return 0; }
@@ -119,4 +120,4 @@ bool usb_is_powered(void)
         return true;
     }
     return false;
-}
\ No newline at end of file
+}
diff --git a/main/power/wslcdtouch2.inc b/main/power/wslcdtouch2.inc
index b2eecc6..720aece 100644
--- a/main/power/wslcdtouch2.inc
+++ b/main/power/wslcdtouch2.inc
@@ -1,4 +1,4 @@
-// Waveshare LCD Touch 2 implementation
+// Waveshare S3 Touch LCD 2 implementation
 //
 #include <driver/gpio.h>
 #include <driver/ledc.h>
@@ -18,7 +18,7 @@
 
 #define BATTERY_ADC_CHANNEL ADC_CHANNEL_4
 #define BATTERY_ADC_ATTEN ADC_ATTEN_DB_12
-#define BATTERY_EMA_ALPHA 0.3 // estimated moving average smoothing factor
+#define BATTERY_EMA_ALPHA 0.3f // estimated moving average smoothing factor
 
 #define LCD_BL_LEDC_TIMER LEDC_TIMER_0
 #define LCD_BL_LEDC_MODE LEDC_LOW_SPEED_MODE
@@ -31,7 +31,7 @@
 static adc_oneshot_unit_handle_t adc1_handle = NULL;
 static adc_cali_handle_t adc1_cali_chan0_handle = NULL;
 
-static int ema_voltage = 0;
+static float ema_voltage = 0.0f;
 
 static void button_shutdown(void* arg, void* ctx)
 {
@@ -48,21 +48,17 @@ static esp_err_t boot_button_init(void)
         .long_press_time = CONFIG_BUTTON_LONG_PRESS_TIME_MS,
         .short_press_time = CONFIG_BUTTON_SHORT_PRESS_TIME_MS,
     };
-
     const button_gpio_config_t btn_gpio_cfg = {
         .gpio_num = 0,
         .active_level = 0,
     };
-
     button_handle_t btn_handle = NULL;
     ESP_ERROR_CHECK(iot_button_new_gpio_device(&btn_cfg, &btn_gpio_cfg, &btn_handle));
     ESP_ERROR_CHECK(iot_button_register_cb(btn_handle, BUTTON_LONG_PRESS_HOLD, NULL, button_shutdown, NULL));
-
     esp_sleep_disable_wakeup_source(ESP_SLEEP_WAKEUP_ALL);
     gpio_hold_en(GPIO_NUM_0);
     gpio_deep_sleep_hold_en();
     esp_sleep_enable_ext0_wakeup(GPIO_NUM_0, 0);
-
     return ESP_OK;
 }
 
@@ -71,14 +67,12 @@ static esp_err_t brightness_init(void)
     gpio_reset_pin(CONFIG_DISPLAY_PIN_BL);
     gpio_set_direction(CONFIG_DISPLAY_PIN_BL, GPIO_MODE_OUTPUT);
     gpio_set_level(CONFIG_DISPLAY_PIN_BL, 1);
-
     ledc_timer_config_t ledc_timer = { .speed_mode = LCD_BL_LEDC_MODE,
         .timer_num = LCD_BL_LEDC_TIMER,
         .duty_resolution = LCD_BL_LEDC_DUTY_RES,
         .freq_hz = LCD_BL_LEDC_FREQUENCY, // Set output frequency at 5 kHz
         .clk_cfg = LEDC_AUTO_CLK };
     ESP_ERROR_CHECK(ledc_timer_config(&ledc_timer));
-
     ledc_channel_config_t ledc_channel = { .speed_mode = LCD_BL_LEDC_MODE,
         .channel = LCD_BL_LEDC_CHANNEL,
         .timer_sel = LCD_BL_LEDC_TIMER,
@@ -87,7 +81,6 @@ static esp_err_t brightness_init(void)
         .duty = 0, // Set duty to 0%
         .hpoint = 0 };
     ESP_ERROR_CHECK(ledc_channel_config(&ledc_channel));
-
     return ESP_OK;
 }
 
@@ -95,23 +88,20 @@ esp_err_t power_init(void)
 {
     // Use the BOOT button as a sleep/wakeup button
     ESP_ERROR_CHECK(boot_button_init());
-
     // Initialise backlight brightness
     ESP_ERROR_CHECK(brightness_init());
-
     // Initialise the ADC to measure battery level
     adc_oneshot_unit_init_cfg_t init_config1 = {
         .unit_id = ADC_UNIT_1,
     };
     ESP_ERROR_CHECK(adc_oneshot_new_unit(&init_config1, &adc1_handle));
     JADE_ASSERT(adc1_handle);
-
+    // ADC Config
     adc_oneshot_chan_cfg_t config = {
-        .bitwidth = ADC_BITWIDTH_DEFAULT,
         .atten = BATTERY_ADC_ATTEN,
+        .bitwidth = ADC_BITWIDTH_DEFAULT,
     };
     ESP_ERROR_CHECK(adc_oneshot_config_channel(adc1_handle, BATTERY_ADC_CHANNEL, &config));
-
     // Use voltage calibration
     adc_cali_curve_fitting_config_t cali_config = {
         .unit_id = ADC_UNIT_1,
@@ -122,15 +112,12 @@ esp_err_t power_init(void)
         JADE_LOGW("ADC calibration not available, continuing without it");
         adc1_cali_chan0_handle = NULL;
     }
-
     return ESP_OK;
 }
 
 esp_err_t power_shutdown(void) { esp_deep_sleep_start(); }
-
 esp_err_t power_screen_on(void) { return ESP_OK; }
 esp_err_t power_screen_off(void) { return ESP_OK; }
-
 esp_err_t power_backlight_on(uint8_t brightness)
 {
     if (brightness < BACKLIGHT_MIN) {
@@ -138,14 +125,11 @@ esp_err_t power_backlight_on(uint8_t brightness)
     } else if (brightness > BACKLIGHT_MAX) {
         brightness = BACKLIGHT_MAX;
     }
-
     uint32_t duty = (brightness * (LCD_BL_LEDC_DUTY - 1)) / 5;
     ESP_ERROR_CHECK(ledc_set_duty(LCD_BL_LEDC_MODE, LCD_BL_LEDC_CHANNEL, duty));
     ESP_ERROR_CHECK(ledc_update_duty(LCD_BL_LEDC_MODE, LCD_BL_LEDC_CHANNEL));
-
     return ESP_OK;
 }
-
 esp_err_t power_backlight_off(void)
 {
     ESP_ERROR_CHECK(ledc_set_duty(LCD_BL_LEDC_MODE, LCD_BL_LEDC_CHANNEL, 0));
@@ -153,26 +137,22 @@ esp_err_t power_backlight_off(void)
 
     return ESP_OK;
 }
-
 esp_err_t power_camera_on(void) { return ESP_OK; }
 esp_err_t power_camera_off(void) { return ESP_OK; }
 
 uint16_t power_get_vbat(void)
 {
     JADE_ASSERT(adc1_handle);
-
     int raw_adc, voltage;
     ESP_ERROR_CHECK(adc_oneshot_read(adc1_handle, BATTERY_ADC_CHANNEL, &raw_adc));
-
     if (adc1_cali_chan0_handle) {
         adc_cali_raw_to_voltage(adc1_cali_chan0_handle, raw_adc, &voltage);
     } else {
-        voltage = (raw_adc * 3300) / 4095; // mV
+        voltage = (raw_adc * 3300) / 4095;
     }
-
-    // apply Estimated Moving Average since the ADC seems to have a lot of noise
-    ema_voltage = BATTERY_EMA_ALPHA * voltage + (1 - BATTERY_EMA_ALPHA) * (ema_voltage == 0 ? voltage : ema_voltage);
-    /* JADE_LOGI("Raw: %.2dmV, Smoothed: %.2d mV", voltage, ema_voltage); */
+    // Apply Estimated Moving Average (EMA)
+    const float ema_v = (ema_voltage > 0) ? ema_voltage : (float)voltage;
+    ema_voltage = (BATTERY_EMA_ALPHA * voltage) + ((1.0f - BATTERY_EMA_ALPHA) * ema_v);
     return (uint16_t)ema_voltage;
 }
 
@@ -193,10 +173,13 @@ uint8_t power_get_battery_status(void)
     return 0;
 }
 
-// The STAT pin on the charging IC isn't exposed to a GPIO so we cannot read it
-// and can't easily tap it with a wire. There is a charging LED though so you
-// can see if the battery is being charged.
-bool power_get_battery_charging(void) { return 0; }
+bool power_get_battery_charging(void)
+{
+    // The charging IC STAT pin is not connected to GPIO.
+    // Return USB status as a proxy for charging (Dummy status)
+    return usb_is_powered();
+}
+
 uint16_t power_get_ibat_charge(void) { return 0; }
 uint16_t power_get_ibat_discharge(void) { return 0; }
 uint16_t power_get_vusb(void) { return 0; }
@@ -212,12 +195,10 @@ bool usb_is_powered(void)
     if (tud_mounted() && !tud_suspended()) {
         return true;
     }
-
     // Fallback: If voltage is near zero (<1V) but chip is on,
     // we must be running on USB power without a battery.
     if (power_get_vbat() < 1000) {
         return true;
     }
-
     return false;
-}
\ No newline at end of file
+}