feat(variants): add Waveshare ESP32-S3-LR1121

ESP32-S3FH4R2 (4MB flash, 2MB PSRAM, native USB-CDC) with an LR1121.
Pins, the DIO5/DIO6 RF switch table and the 1.8 V TCXO follow the HF
schematic and Waveshare's examples. Envs: repeater, room server,
companion USB/BLE and KISS modem, all on min_spiffs so roles share one
partition layout.

Only RFO_HP_LF is wired (R4 on RFO_LP_LF is not fitted), so the new
opt-in LR1121_FORCE_HP_PA flag keeps RadioLib on the HP PA at <= 14 dBm,
where it would otherwise select the unconnected LP PA.

variants/waveshare_esp32s3_lr1121/target.cpp

@@ -0,0 +1,63 @@
+#include <Arduino.h>
+#include "target.h"
+
+WaveshareS3LR1121Board board;
+
+static SPIClass spi;
+RADIO_CLASS radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, spi);
+WRAPPER_CLASS radio_driver(radio, board);
+
+ESP32RTCClock fallback_clock;
+AutoDiscoverRTCClock rtc_clock(fallback_clock);
+SensorManager sensors;
+
+#ifndef LORA_CR
+  #define LORA_CR 5
+#endif
+
+// DIO5/DIO6 drive the RTC6603SP sub-GHz T/R switch; the 2.4 GHz port (RFIO_HF) is unswitched
+static const uint32_t rfswitch_dios[Module::RFSWITCH_MAX_PINS] = {
+  RADIOLIB_LR11X0_DIO5,
+  RADIOLIB_LR11X0_DIO6,
+  RADIOLIB_NC
+};
+
+static const Module::RfSwitchMode_t rfswitch_table[] = {
+  // mode                 DIO5  DIO6
+  { LR11x0::MODE_STBY,   {LOW,  LOW}},
+  { LR11x0::MODE_RX,     {HIGH, LOW}},
+  { LR11x0::MODE_TX,     {LOW,  HIGH}},
+  { LR11x0::MODE_TX_HP,  {LOW,  HIGH}},
+  { LR11x0::MODE_TX_HF,  {LOW,  LOW}},
+  { LR11x0::MODE_GNSS,   {LOW,  LOW}},
+  { LR11x0::MODE_WIFI,   {LOW,  LOW}},
+  END_OF_MODE_TABLE,
+};
+
+bool radio_init() {
+  fallback_clock.begin();
+  rtc_clock.begin(Wire);
+
+  spi.begin(P_LORA_SCLK, P_LORA_MISO, P_LORA_MOSI);
+  int status = radio.begin(LORA_FREQ, LORA_BW, LORA_SF, LORA_CR, RADIOLIB_LR11X0_LORA_SYNC_WORD_PRIVATE,
+                           LORA_TX_POWER, 16, LR11X0_DIO3_TCXO_VOLTAGE);
+  if (status != RADIOLIB_ERR_NONE) {
+    Serial.print("ERROR: radio init failed: ");
+    Serial.println(status);
+    return false;
+  }
+
+  radio.setCRC(2);
+  radio.explicitHeader();
+  radio.setRfSwitchTable(rfswitch_dios, rfswitch_table);
+#ifdef RX_BOOSTED_GAIN
+  radio.setRxBoostedGainMode(RX_BOOSTED_GAIN);
+#endif
+
+  return true;
+}
+
+mesh::LocalIdentity radio_new_identity() {
+  RadioNoiseListener rng(radio);
+  return mesh::LocalIdentity(&rng);
+}