feat(techo-lite): add Non-Shell (screenless) companion BLE variant

T-Echo Lite Non-Shell has no ePaper display, but the existing
companion BLE env inherits DISPLAY_CLASS=GxEPDDisplay from the base
env. This causes display.begin() to run on non-existent hardware,
corrupting BLE initialization and generating a random PIN that
cannot be displayed, making BLE connection impossible.

Add LilyGo_T-Echo-Lite_non_shell_companion_radio_ble env that:
- excludes DISPLAY_CLASS and ePaper-related build flags
- removes GxEPDDisplay.cpp and ui-new from build sources
- uses static BLE_PIN_CODE=123456 (avoids random PIN generation)

Also fix boards/t-echo.json:
- add nrfutil to upload protocols list
- add use_1200bps_touch=true and wait_for_upload_port=true
  to enable reliable flashing via PlatformIO upload button

boards/t-echo.json

@@ -53,11 +53,14 @@
     "protocols": [
       "jlink",
       "nrfjprog",
+      "nrfutil",
       "stlink",
       "cmsis-dap",
       "blackmagic"
-    ]
+    ],
+    "use_1200bps_touch": true,
+    "wait_for_upload_port": true
   },
   "url": "https://os.mbed.com/platforms/Nordic-nRF52840-DK/",
   "vendor": "Nordic"
-}
+}

variants/lilygo_techo_lite/platformio.ini

@@ -96,3 +96,47 @@ build_src_filter = ${LilyGo_T-Echo-Lite.build_src_filter}
 lib_deps =
   ${LilyGo_T-Echo-Lite.lib_deps}
   densaugeo/base64 @ ~1.4.0
+
+[env:LilyGo_T-Echo-Lite_non_shell_companion_radio_ble]
+extends = LilyGo_T-Echo-Lite
+upload_protocol = nrfutil
+board_build.ldscript = boards/nrf52840_s140_v6_extrafs.ld
+board_upload.maximum_size = 712704
+build_flags =
+  ${nrf52_base.build_flags}
+  -I variants/lilygo_techo_lite
+  -I src/helpers/nrf52
+  -I lib/nrf52/s140_nrf52_6.1.1_API/include
+  -I lib/nrf52/s140_nrf52_6.1.1_API/include/nrf52
+  -I src/helpers/ui
+  -I examples/companion_radio/ui-new
+  -D LILYGO_TECHO
+  -D RADIO_CLASS=CustomSX1262
+  -D WRAPPER_CLASS=CustomSX1262Wrapper
+  -D LORA_TX_POWER=22
+  -D SX126X_POWER_EN=30
+  -D SX126X_CURRENT_LIMIT=140
+  -D SX126X_RX_BOOSTED_GAIN=1
+  -D P_LORA_TX_LED=LED_GREEN
+  -D DISABLE_DIAGNOSTIC_OUTPUT
+  -D ENV_INCLUDE_GPS=1
+  -D GPS_BAUD_RATE=9600
+  -D PIN_GPS_EN=GPS_EN
+  -D AUTO_OFF_MILLIS=0
+  -D MAX_CONTACTS=350
+  -D MAX_GROUP_CHANNELS=40
+  -D BLE_PIN_CODE=123456
+  -D OFFLINE_QUEUE_SIZE=256
+  -D UI_RECENT_LIST_SIZE=9
+  -D AUTO_SHUTDOWN_MILLIVOLTS=3300
+build_src_filter = ${nrf52_base.build_src_filter}
+  +<helpers/*.cpp>
+  +<TechoBoard.cpp>
+  +<helpers/sensors/EnvironmentSensorManager.cpp>
+  +<helpers/ui/MomentaryButton.cpp>
+  +<../variants/lilygo_techo_lite>
+  +<helpers/nrf52/SerialBLEInterface.cpp>
+  +<../examples/companion_radio/*.cpp>
+lib_deps =
+  ${LilyGo_T-Echo-Lite.lib_deps}
+  densaugeo/base64 @ ~1.4.0