refctor: TankInfo structure (consistent layout)

- fix: use tagged enum serialization for TankError
- fix: rename TankInfo fields for consistent naming (volume_ml, pct, water_temp_c)
- renamed some fields for better clarity on contained value

rust/src/hal/battery.rs

@@ -28,7 +28,7 @@ pub trait BatteryInteraction {
 #[derive(Debug, Serialize)]
 pub struct BatteryInfo {
     pub voltage_mv: Option<u16>,
-    pub current_ma: Option<i16>,
+    pub avg_current_ma: Option<i16>,
     pub soc_pct: Option<f32>,
     pub soh_pct: Option<u16>,
     pub temperature_c: Option<u16>,
@@ -183,7 +183,7 @@ impl BatteryInteraction for BQ34Z100G1 {
     async fn get_battery_state(&mut self) -> FatResult<BatteryState> {
         Ok(BatteryState::Info(BatteryInfo {
             voltage_mv: Some(self.voltage_milli_volt().await?),
-            current_ma: Some(self.average_current_milli_ampere().await?),
+            avg_current_ma: Some(self.average_current_milli_ampere().await?),
             soc_pct: Some(self.state_charge_percent().await?),
             soh_pct: Some(self.state_health_percent().await?),
             temperature_c: Some(self.bat_temperature().await?),

rust/src/main.rs

@@ -866,7 +866,7 @@ async fn publish_battery_state(
         Ok(BatteryState::Info(info)) => info,
         Ok(BatteryState::Unknown) => BatteryInfo {
             voltage_mv: None,
-            current_ma: None,
+            avg_current_ma: None,
             soc_pct: None,
             soh_pct: None,
             temperature_c: None,
@@ -877,7 +877,7 @@ async fn publish_battery_state(
         },
         Err(e) => BatteryInfo {
             voltage_mv: None,
-            current_ma: None,
+            avg_current_ma: None,
             soc_pct: None,
             soh_pct: None,
             temperature_c: None,

rust/src/tank.rs

@@ -144,13 +144,13 @@ impl TankState {
             warn_level,
             volume_ml: left_ml,
             sensor_error: tank_err,
-            raw,
+            fill_raw_v: raw,
             water_frozen: water_temp
                 .as_ref()
                 .is_ok_and(|temp| *temp < WATER_FROZEN_THRESH),
             water_temp_c: water_temp.as_ref().copied().ok(),
             temp_sensor_error: water_temp.as_ref().err().map(|err| err.to_string()),
-            pct: percent,
+            fill_pct: percent,
         }
     }
 }
@@ -184,9 +184,9 @@ pub struct TankInfo {
     /// if there is an issue with the water level sensor
     pub(crate) sensor_error: Option<TankError>,
     /// raw water sensor value
-    pub(crate) raw: Option<f32>,
+    pub(crate) fill_raw_v: Option<f32>,
     /// percent value
-    pub(crate) pct: Option<f32>,
+    pub(crate) fill_pct: Option<f32>,
     /// water in the tank might be frozen
     pub(crate) water_frozen: bool,
     /// water temperature