Add LilyGO T-Beam 1W support (#8967)

* Add LilyGO T-Beam 1W support
- Add board definition and variant files for ESP32-S3 based T-Beam 1W
- Add RF95_FAN_EN support to SX126xInterface for PA cooling fan
- Add SX126X_PA_RAMP_US for configurable PA ramp time (800us for 1W PA)
- Configure RF switch: DIO2 for PA, GPIO 21 for LNA control

* Set TX_GAIN_LORA to 10dB per PR feedback (offset for 1W PA)

* Apply suggestion from @Copilot

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Ben Meadors <benmmeadors@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

variants/esp32s3/t-beam-1w/pins_arduino.h

@@ -0,0 +1,25 @@
+#ifndef Pins_Arduino_h
+#define Pins_Arduino_h
+
+#include <stdint.h>
+
+#define USB_VID 0x303a
+#define USB_PID 0x1001
+
+static const uint8_t TX = 43;
+static const uint8_t RX = 44;
+
+// I2C for OLED and sensors
+static const uint8_t SDA = 8;
+static const uint8_t SCL = 9;
+
+// Default SPI mapped to Radio/SD
+static const uint8_t SS = 15;   // LoRa CS
+static const uint8_t MOSI = 11;
+static const uint8_t MISO = 12;
+static const uint8_t SCK = 13;
+
+// SD Card CS
+#define SDCARD_CS 10
+
+#endif /* Pins_Arduino_h */

variants/esp32s3/t-beam-1w/platformio.ini

@@ -0,0 +1,14 @@
+; LilyGo T-Beam-1W (1 Watt LoRa with external PA)
+[env:t-beam-1w]
+extends = esp32s3_base
+board = t-beam-1w
+board_build.partitions = default_8MB.csv
+board_check = true
+
+lib_deps =
+  ${esp32s3_base.lib_deps}
+
+build_flags = 
+  ${esp32s3_base.build_flags} 
+  -I variants/esp32s3/t-beam-1w
+  -D T_BEAM_1W

variants/esp32s3/t-beam-1w/variant.h

@@ -0,0 +1,97 @@
+// LilyGo T-Beam-1W variant.h  
+// Configuration based on LilyGO utilities.h and RF documentation
+
+// I2C for OLED display (SH1106 at 0x3C)
+#define I2C_SDA 8
+#define I2C_SCL 9
+
+// GPS - Quectel L76K
+#define GPS_RX_PIN 5
+#define GPS_TX_PIN 6
+#define GPS_1PPS_PIN 7
+#define GPS_WAKEUP_PIN 16  // GPS_EN_PIN in LilyGO code
+#define HAS_GPS 1
+#define GPS_BAUDRATE 9600
+
+// Buttons
+#define BUTTON_PIN 0         // BUTTON 1
+#define BUTTON_PIN_ALT 17    // BUTTON 2
+
+// SPI (shared by LoRa and SD)
+#define SPI_MOSI 11
+#define SPI_SCK 13
+#define SPI_MISO 12
+#define SPI_CS 10
+
+// SD Card
+#define HAS_SDCARD
+#define SDCARD_USE_SPI1
+#define SDCARD_CS SPI_CS
+
+// LoRa Radio - SX1262 with 1W PA
+#define USE_SX1262
+
+#define LORA_SCK SPI_SCK
+#define LORA_MISO SPI_MISO  
+#define LORA_MOSI SPI_MOSI
+#define LORA_CS 15
+#define LORA_RESET 3
+#define LORA_DIO1 1
+#define LORA_BUSY 38
+
+// CRITICAL: Radio power enable - MUST be HIGH before lora.begin()!
+// GPIO 40 powers the SX1262 + PA module via LDO
+#define SX126X_POWER_EN 40
+
+// TX power offset for external PA (0 = no offset, full SX1262 power)
+#define TX_GAIN_LORA 10
+
+#ifdef USE_SX1262
+#define SX126X_CS LORA_CS
+#define SX126X_DIO1 LORA_DIO1
+#define SX126X_BUSY LORA_BUSY
+#define SX126X_RESET LORA_RESET
+
+// RF switching configuration for 1W PA module
+// DIO2 controls PA (via SX126X_DIO2_AS_RF_SWITCH)
+// CTRL PIN (GPIO 21) controls LNA - must be HIGH during RX
+// Truth table: DIO2=1,CTRL=0 → TX (PA on, LNA off)
+//              DIO2=0,CTRL=1 → RX (PA off, LNA on)
+#define SX126X_DIO2_AS_RF_SWITCH
+#define SX126X_RXEN 21  // LNA enable - HIGH during RX
+
+// TCXO voltage - required for radio init
+#define SX126X_DIO3_TCXO_VOLTAGE 1.8
+
+#define SX126X_MAX_POWER 22
+#endif
+
+// LED
+#define LED_PIN 18
+#define LED_STATE_ON 1  // HIGH = ON
+
+// Battery ADC
+#define BATTERY_PIN 4
+#define ADC_CHANNEL ADC1_GPIO4_CHANNEL
+#define BATTERY_SENSE_SAMPLES 30
+#define ADC_MULTIPLIER 2.9333
+
+// NTC temperature sensor
+#define NTC_PIN 14
+
+// Fan control
+#define FAN_CTRL_PIN 41
+// Meshtastic standard fan control pin macro
+#define RF95_FAN_EN FAN_CTRL_PIN
+
+// PA Ramp Time - T-Beam 1W requires >800us stabilization (default is 200us)
+// Value 0x05 = RADIOLIB_SX126X_PA_RAMP_800U
+#define SX126X_PA_RAMP_US 0x05
+
+// Display - SH1106 OLED (128x64)
+#define USE_SH1106 
+#define OLED_WIDTH 128
+#define OLED_HEIGHT 64
+
+// 32768 Hz crystal present
+#define HAS_32768HZ 1