feat(ui-lvgl): quick panel from the status bar; L2 fixes from rc1

The quick panel, as a phone's: pulled down from the status bar (or a tap
on it). Bluetooth, WiFi, GPS, sound, trail and live share switch at a
tap; Advert opens the advert popup (moved here from the Nodes header);
Lock locks the screen; a brightness slider. Holding a tile opens its
settings. Lock and sun glyphs added to the fonts.

Fixes from rc1 testing on the L2:
- GPS status icon: none when GPS is off (the module kept its last fix
  valid, so it stayed green); grey on, green with a fix. ensureGps()
  turns GPS on before trusting that stale fix.
- Screen wake: the panel wakes dark, a frame is drawn, then the
  backlight fades in -- no white flash. Off fades out first.
- Power off / flat battery: the chip wakes every 30 s to look for USB
  power and starts when plugged in (it slept with no wake source before,
  until the reset button). Plugged in when switched off: stays off until
  re-plugged.
- Message ages in a conversation refresh every 2 s, as on ui-new; the
  message popup keeps its age, repeaters heard and delivery up to date.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/companion_radio/ui-lvgl/Theme.h

@@ -58,6 +58,8 @@ namespace theme {
   #define UI_SYMBOL_KEY     "\xEF\x82\x84"   // U+F084, admin
   #define UI_SYMBOL_ROUTE   "\xEF\x93\x97"   // U+F4D7, trail
   #define UI_SYMBOL_MUTE    "\xEF\x9A\xA9"   // U+F6A9, muted (speaker with a cross)
+  #define UI_SYMBOL_LOCK    "\xEF\x80\xA3"   // U+F023, quick panel: lock the screen
+  #define UI_SYMBOL_SUN     "\xEF\x86\x85"   // U+F185, quick panel: brightness
 
   // Accent choices; the fill is the colour at 42% over the background.
   struct Accent { const char* name; uint32_t col; };