feat(boards): add M5Stack Cardputer ADV and LilyGO T-Echo Lite KeyShield

New M5Stack Cardputer ADV variant (ESP32-S3, ST7789 TFT, built-in TCA8418
QWERTY keyboard, PI4IOE5V6408 LoRa-cap IO-expander autodetect), and a
KeyShield accessory variant for the existing LilyGO T-Echo Lite (external
TCA8418 T9 keypad + AW21009 backlight driver). Both keyboards share one
ENV_USE_TCA8418 polling block in UITask.cpp::loop(), coexisting with the
unrelated CardKB support (different chip/address/flag).

Fixes carried in from the contributed T-Echo Lite code: swapped GPS RX/TX
pins, TX-LED hooks, TCXO voltage, missing GxEPD2_122_T61 panel include.
Fixed during integration: I2C bus was probed for an RTC before Wire.begin()
configured its pins on Cardputer ADV (silent RTC autodetect failure).

Added dedicated *_solo_dual release envs for both boards (auto-picked up by
the solo-firmware release workflow). Gave the T-Echo Lite KeyShield solo
build -Os/-Ofast-unflag like every other nRF52 solo build (was missing,
cut flash usage from 90.7% to 61.4%).

Ported the shared misc-fixed 6x9 font (full Latin/Greek/Cyrillic, opt-in via
OLED_MISC_FIXED_FONT) to ST7789Display for the Cardputer's on-screen
keyboard. ST7789Spi isn't Adafruit_GFX-based like the other single-font
drivers, and this panel's logical->physical scale is non-integer, so glyphs
are re-packed to XBM and blitted through the existing drawXbm(), which
already does correct fractional-scale boundary math, rather than
duplicating that logic.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

variants/m5stack_cardputer_adv/target.cpp

@@ -0,0 +1,63 @@
+#include <Arduino.h>
+#include "target.h"
+
+CardputerADVBoard 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);
+MicroNMEALocationProvider gps(Serial1, &rtc_clock);
+EnvironmentSensorManager sensors(gps);
+
+#ifdef DISPLAY_CLASS
+  DISPLAY_CLASS display;
+  MomentaryButton user_btn(PIN_USER_BTN, 1000, true);
+#endif
+
+static void init_lora_cap_ioe() {
+  const uint8_t PI4IOE_ADDR = 0x43; // PI4IOE5V6408, ADDR pin -> GND
+
+  // Egyszerű "probe": ha nincs ACK, nincs ott az IO expander (régi cap)
+  Wire.beginTransmission(PI4IOE_ADDR);
+  if (Wire.endTransmission() != 0) {
+    return; // régi Cap LoRa868, nincs teendő
+  }
+
+  // Új Cap LoRa-1262: P0 -> output, High-Z letiltva, majd HIGH
+  Wire.beginTransmission(PI4IOE_ADDR);
+  Wire.write(0x03);   // I/O Direction register
+  Wire.write(0x01);   // bit0 = 1 -> P0 kimenet, többi marad bemenet
+  Wire.endTransmission();
+
+  Wire.beginTransmission(PI4IOE_ADDR);
+  Wire.write(0x07);   // Output High-Impedance register
+  Wire.write(0x00);   // bit0 = 0 -> P0 kijön a High-Z állapotból
+  Wire.endTransmission();
+
+  Wire.beginTransmission(PI4IOE_ADDR);
+  Wire.write(0x05);   // Output Port register
+  Wire.write(0x01);   // bit0 = 1 -> P0 HIGH (LoRa "SW" pin engedélyezve)
+  Wire.endTransmission();
+}
+
+bool radio_init() {
+  fallback_clock.begin();
+
+  Wire.begin(PIN_BOARD_SDA, PIN_BOARD_SCL);   // 14pin header & internal
+  Wire1.begin(PIN_BOARD_SDA1, PIN_BOARD_SCL1); // grove
+
+  rtc_clock.begin(Wire);   // needs Wire already begun on the right pins to auto-detect an RTC chip
+
+  init_lora_cap_ioe();
+
+  return radio.std_init(&spi);
+}
+
+mesh::LocalIdentity radio_new_identity() {
+  RadioNoiseListener rng(radio);
+  return mesh::LocalIdentity(&rng); // create new random identity
+}