Refactor extra1 to fertilizer_pump in HAL and main logic

- Renamed `extra1` method and related calls to `fertilizer_pump` for clarity and better domain alignment.
- Updated HAL implementation to control `extra2` GPIO for fertilizer pump operations.
- Added build script trigger to refresh `VERGEN_BUILD_TIMESTAMP` on each build.

Software/MainBoard/rust/src/hal/v4_hal.rs

@@ -484,11 +484,11 @@ impl<'a> BoardInteraction<'a> for V4<'a> {
         Ok(())
     }
 
-    async fn extra1(&mut self, enable: bool) -> FatResult<()> {
+    async fn fertilizer_pump(&mut self, enable: bool) -> FatResult<()> {
         if enable {
-            self.extra1.set_high();
+            self.extra2.set_high();
         } else {
-            self.extra1.set_low();
+            self.extra2.set_low();
         }
         Ok(())
     }