fix(ui): wake display on T-Echo KeyShield Home key, drop dead code

Home key toggles the keyboard backlight but wasn't going through
checkDisplayOn() like every other TCA8418 key, so it couldn't wake a
sleeping display or extend the auto-off timer.

Also: removed a no-op #elif branch in ST7789Display.cpp (same values as
the #else it duplicated), and ENABLE_SCREENSHOT on the Cardputer ADV
solo env, which does nothing since ST7789Display has no getBuffer().

examples/companion_radio/ui-new/UITask.cpp

@@ -2346,6 +2346,7 @@ void UITask::loop() {
       case KEY_DOWN:  enqueueKey(checkDisplayOn(KEY_DOWN));  break;
       case KEY_CANCEL:enqueueKey(checkDisplayOn(KEY_CANCEL));break;
       case KEY_HOME:
+        checkDisplayOn(k);   // wake/extend same as every other key here, even though Home has no nav action
         #ifdef LILYGO_TECHO_LITE_KEYSHIELD
         extern void techo_keyshield_backlight_toggle();
         techo_keyshield_backlight_toggle();

src/helpers/ui/ST7789Display.cpp

@@ -18,11 +18,8 @@
 #ifdef HELTEC_VISION_MASTER_T190
   #define SCALE_X  2.5f        // 320 / 128
   #define SCALE_Y  2.65625f    // 170 / 64
-#elif defined(CARDPUTER_ADV)
-  #define SCALE_X  1.875f      // 240 / 128
-  #define SCALE_Y  2.109375f   // 135 / 64
 #else
-  #define SCALE_X  1.875f      // 240 / 128
+  #define SCALE_X  1.875f      // 240 / 128 -- also Cardputer ADV's panel, same resolution
   #define SCALE_Y  2.109375f   // 135 / 64
 #endif
 

variants/m5stack_cardputer_adv/platformio.ini

@@ -110,7 +110,6 @@ build_flags =
   -D FIRMWARE_SOLO_BUILD=1
   -D MESHCORE_VERSION='"1.17"'
   -D UI_SENSORS_PAGE=1
-  -D ENABLE_SCREENSHOT
   ; misc-fixed 6x9 font (full Latin/Greek/Cyrillic), same as the Wio L1/Heltec
   ; solo builds. Solo only: it costs ~14 KB of flash, and this board's own
   ; QWERTY keyboard is exactly the case that benefits from typing those