feat(gat562-30s): add solo build envs, fix joystick/GPS/buzzer/display

- SSD1306Display: track _text_sz in setTextSize(); override getCharWidth()
  and getLineHeight() so line spacing scales with text size (fixes text
  overlap on splash/clock screens at size 2)
- gat562_30s_mesh_kit variant.h: fix PIN_GPS_EN 33→34 (IO2/P1.02 controls
  GPS module power via Q3/Q5 transistors; 33 = BEE_EN = buzzer)
- gat562_30s_mesh_kit variant.h: correct joystick pin comments (P0.xx labels
  were cyclically wrong; pin numbers already correct)
- gat562_30s_mesh_kit target.h/cpp: declare and instantiate joystick_up/down
  under UI_HAS_JOYSTICK_UPDOWN guard (fixes compile error in solo envs)
- gat562_30s_mesh_kit platformio.ini: add solo_ble and solo_dual environments
  with GPS, BLE, joystick up/down, QSPI flash, and buzzer (NonBlockingRTTTL)
- gat562_mesh_watch13 platformio.ini: add solo_ble environment with GPS

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

variants/gat562_mesh_watch13/platformio.ini

@@ -87,6 +87,45 @@ lib_deps =
   ${GAT562_Mesh_Watch13.lib_deps}
   densaugeo/base64 @ ~1.4.0
 
+[env:GAT562_Mesh_Watch13_solo_ble]
+extends = GAT562_Mesh_Watch13
+board_build.ldscript = boards/nrf52840_s140_v6_extrafs.ld
+board_upload.maximum_size = 712704
+build_flags =
+  ${GAT562_Mesh_Watch13.build_flags}
+  -I examples/companion_radio/ui-new
+  -D DISPLAY_CLASS=SSD1306Display
+  -D MAX_CONTACTS=350
+  -D MAX_GROUP_CHANNELS=40
+  -D BLE_PIN_CODE=123456
+  -D OFFLINE_QUEUE_SIZE=256
+  -D FIRMWARE_SOLO_BUILD=1
+  -D MESHCORE_VERSION='"1.17"'
+  -D UI_SENSORS_PAGE=1
+  -D ADVERT_NAME='"@@MAC"'
+  ; GPS — re-enable (base undefines it); Serial1 pins 15/16 from variant
+  -D ENV_INCLUDE_GPS=1
+  -D GPS_BAUD_RATE=9600
+  ; Buzzer available on IO3 (pin 21) — uncomment to enable
+;  -D PIN_BUZZER=21
+;  -D PIN_VIBRATION=36
+;  -D MESH_PACKET_LOGGING=1
+;  -D MESH_DEBUG=1
+build_src_filter = ${GAT562_Mesh_Watch13.build_src_filter}
+  +<helpers/nrf52/SerialBLEInterface.cpp>
+  +<helpers/ui/MomentaryButton.cpp>
+  +<helpers/ui/GenericVibration.cpp>
+  +<../examples/companion_radio/*.cpp>
+  +<../examples/companion_radio/ui-new/*.cpp>
+; If PIN_BUZZER is enabled above, also add:
+;  +<helpers/ui/buzzer.cpp>
+lib_deps =
+  ${GAT562_Mesh_Watch13.lib_deps}
+  adafruit/RTClib @ ^2.1.3
+  densaugeo/base64 @ ~1.4.0
+; If PIN_BUZZER is enabled, also add:
+;  end2endzone/NonBlockingRTTTL@^1.3.0
+
 [env:GAT562_Mesh_Watch13_kiss_modem]
 extends = GAT562_Mesh_Watch13
 build_src_filter = ${GAT562_Mesh_Watch13.build_src_filter}