Add Waveshare ESP32-C3-Zero support

Add support for the Waveshare ESP32-C3-Zero, including BLE, USB, Wi-Fi, repeater, and room server builds.

variants/waveshare_c3_zero/target.cpp

@@ -0,0 +1,46 @@
+#include <Arduino.h>
+#include "target.h"
+
+WaveshareC3ZeroBoard board;
+
+#if defined(P_LORA_SCLK)
+  // NOTE: ESP32-C3 only exposes one general-purpose SPI peripheral (FSPI).
+  // The default SPIClass() constructor does not reliably bind to it on this
+  // chip, which silently produces an SPI object that never talks to real
+  // hardware -- radio chip-detection then fails every time with no error
+  // other than RADIOLIB_ERR_CHIP_NOT_FOUND. Always pass FSPI explicitly.
+  static SPIClass spi(FSPI);
+  RADIO_CLASS radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, spi);
+#else
+  RADIO_CLASS radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY);
+#endif
+
+WRAPPER_CLASS radio_driver(radio, board);
+
+ESP32RTCClock fallback_clock;
+AutoDiscoverRTCClock rtc_clock(fallback_clock);
+
+#if ENV_INCLUDE_GPS
+  #include <helpers/sensors/MicroNMEALocationProvider.h>
+  MicroNMEALocationProvider nmea = MicroNMEALocationProvider(Serial1, &rtc_clock);
+  EnvironmentSensorManager sensors = EnvironmentSensorManager(nmea);
+#else
+  EnvironmentSensorManager sensors;
+#endif
+
+bool radio_init() {
+  fallback_clock.begin();
+  rtc_clock.begin(Wire);
+
+#if defined(P_LORA_SCLK)
+  spi.begin(P_LORA_SCLK, P_LORA_MISO, P_LORA_MOSI);
+  return radio.std_init(&spi);
+#else
+  return radio.std_init();
+#endif
+}
+
+mesh::LocalIdentity radio_new_identity() {
+  RadioNoiseListener rng(radio);
+  return mesh::LocalIdentity(&rng);  // create new random identity
+}