feat(wio-tracker-l1): add settings screen and companion radio improvements

Settings screen (UI_HAS_JOYSTICK_UPDOWN build variant):
- Display brightness (5 levels, contrast curve tuned for SH1106 non-linearity)
- Buzzer on/off (respected at startup, no more forced unmute)
- TX power (2–22 dBm)
- Auto-off delay (5s / 15s / 30s / 60s / never)
- GPS update interval (off / 30s / 1min / 5min / 15min / 30min)
- Timezone offset (UTC-12..+14) for clock screen
- Low battery auto-shutdown threshold (off / 3.0–3.5V, default 3.4V)
- Battery display mode (icon / % / voltage)

Battery:
- EMA filter (alpha=0.2) on ADC readings to smooth voltage spikes from uneven load
- Battery % calculated using low_batt_mv as 0% anchor
- Mute icon repositions dynamically based on battery display width

Clock screen on HomeScreen showing time/date with timezone support.

Build:
- _settings variants added for USB and BLE companion radio builds
- Automatic UF2 generation on every build via create-uf2.py post-script
- UI_HAS_JOYSTICK_UPDOWN flag guards joystick_up/down to avoid breaking other boards

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

create-uf2.py

@@ -21,6 +21,8 @@ def create_uf2_action(source, target, env):
     )
     env.Execute(uf2_cmd)
 
+env.AddPostAction(firmware_hex, create_uf2_action)
+
 env.AddCustomTarget(
     name="create_uf2",
     dependencies=firmware_hex,