refactor: simplify battery monitoring logic, remove unused fields, and replace BQ34Z100G1 integration with WCH I2C implementation

Software/MainBoard/rust/src/log/mod.rs

@@ -280,6 +280,8 @@ pub enum LogMessage {
     PumpOpenLoopCurrent,
     #[strum(serialize = "Pump Open current sensor required but did not work: ${number_a}")]
     PumpMissingSensorCurrent,
+    #[strum(serialize = "MPPT Current sensor could not be reached")]
+    MPPTError,
 }
 
 #[derive(Serialize)]