fix(lua): Re-implement luaSetSerialBaudrate (#4501)

radio/src/serial.cpp

@@ -379,6 +379,38 @@ void serialSetPower(uint8_t port_nr, bool enabled)
 }
 #endif
 
+uint32_t serialGetBaudrate(uint8_t port_nr)
+{
+  auto state = getSerialPortState(port_nr);
+  if (!state || !state->port || !state->usart_ctx)
+    return 0;
+
+  auto port = state->port;
+  if (!port->uart || !port->uart->getBaudrate) return 0;
+
+  return port->uart->getBaudrate(state->usart_ctx);
+}
+
+void serialSetBaudrate(uint8_t port_nr, uint32_t baudrate)
+{
+  auto state = getSerialPortState(port_nr);
+  if (!state || !state->port || !state->usart_ctx)
+    return;
+
+  auto port = state->port;
+  if (!port->uart || !port->uart->setBaudrate) return;
+
+  port->uart->setBaudrate(state->usart_ctx, baudrate);
+}
+
+int serialGetModePort(int mode)
+{
+  for (int p = 0; p < MAX_SERIAL_PORTS; p++) {
+    if (serialGetMode(p) == mode) return p;
+  }
+  return -1;  
+}
+
 void serialInit(uint8_t port_nr, int mode)
 {
   auto state = getSerialPortState(port_nr);