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/esp.rs

@@ -120,6 +120,15 @@ pub struct Esp<'a> {
 // CPU cores/threads, reconsider this.
 unsafe impl Send for Esp<'_> {}
 
+macro_rules! mk_static {
+    ($t:ty,$val:expr) => {{
+        static STATIC_CELL: static_cell::StaticCell<$t> = static_cell::StaticCell::new();
+        #[deny(unused_attributes)]
+        let x = STATIC_CELL.uninit().write(($val));
+        x
+    }};
+}
+
 impl Esp<'_> {
     pub fn get_time(&self) -> DateTime<Utc> {
         DateTime::from_timestamp_micros(self.rtc.current_time_us() as i64)

rust/src/hal/mod.rs

@@ -282,7 +282,14 @@ pub struct FreePeripherals<'a> {
     pub adc1: ADC1<'a>,
 }
 
-use crate::util::mk_static;
+macro_rules! mk_static {
+    ($t:ty,$val:expr) => {{
+        static STATIC_CELL: static_cell::StaticCell<$t> = static_cell::StaticCell::new();
+        #[deny(unused_attributes)]
+        let x = STATIC_CELL.uninit().write(($val));
+        x
+    }};
+}
 
 impl PlantHal {
     pub async fn create() -> Result<Mutex<CriticalSectionRawMutex, HAL<'static>>, FatError> {

rust/src/main.rs

@@ -71,7 +71,6 @@ mod mqtt;
 mod network;
 mod plant_state;
 mod tank;
-mod util;
 mod webserver;
 
 extern crate alloc;

rust/src/mqtt.rs

@@ -110,7 +110,14 @@ async fn publish_inner(subtopic: &str, message: &str) -> FatResult<()> {
     }
 }
 
-use crate::util::mk_static;
+macro_rules! mk_static {
+    ($t:ty,$val:expr) => {{
+        static STATIC_CELL: static_cell::StaticCell<$t> = static_cell::StaticCell::new();
+        #[deny(unused_attributes)]
+        let x = STATIC_CELL.uninit().write(($val));
+        x
+    }};
+}
 
 pub async fn mqtt_init(
     network_config: &'static NetworkConfig,

rust/src/network.rs

@@ -3,7 +3,6 @@ use crate::config::NetworkConfig;
 use crate::fat_error::{ContextExt, FatError, FatResult};
 use crate::hal::{PlantHal, HAL};
 use crate::mqtt;
-use crate::util::mk_static;
 use alloc::string::{String, ToString};
 use alloc::sync::Arc;
 use chrono::{DateTime, Utc};
@@ -197,6 +196,15 @@ pub(crate) async fn run_dhcp(stack: Stack<'static>, ip: Ipv4Addr) {
     }
 }
 
+macro_rules! mk_static {
+    ($t:ty,$val:expr) => {{
+        static STATIC_CELL: static_cell::StaticCell<$t> = static_cell::StaticCell::new();
+        #[deny(unused_attributes)]
+        let x = STATIC_CELL.uninit().write(($val));
+        x
+    }};
+}
+
 pub async fn wifi_ap(
     ssid: String,
     interface_ap: Interface<'static>,

rust/src/util.rs

@@ -1,10 +0,0 @@
-macro_rules! mk_static {
-    ($t:ty,$val:expr) => {{
-        static STATIC_CELL: static_cell::StaticCell<$t> = static_cell::StaticCell::new();
-        #[deny(unused_attributes)]
-        let x = STATIC_CELL.uninit().write(($val));
-        x
-    }};
-}
-
-pub(crate) use mk_static;