feat(f722): enforce board policy and emit diagnostics

platforms/stm32f7/src/f722/peripherals/usart.rs

@@ -1,9 +1,10 @@
 //! STM32F722 USART routes used by supported boards.
 
+use kaptan_log::KaptanError;
 use stm32f7::stm32f722;
 
 /// UART baud-rate configuration error.
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, KaptanError)]
 pub enum BaudRateError {
     /// Zero is not a valid baud rate.
     Zero,