feat(ui-lvgl): LVGL 9 skeleton frontend for Wio Tracker L2

New examples/companion_radio/ui-lvgl/ over the shared UI Core (env
Wio_Tracker_L2_companion_solo_lvgl, LVGL 9.2.2, pool in PSRAM):
status bar, home (clock, unread), conversation list (channels + recent
DMs with unread badges), contact picker, conversation view with bubbles,
delivery / relay markers and on-screen keyboard, toasts for Core events,
display auto-off with wake on touch / button. Board glue (LovyanGFX
flush + GT911 touch) isolated in LvglPort.h; design tokens in Theme.h.

UiCore gains the first frontend actions, sendDirectText() and
sendChannelText(), and drives DM auto-resend + unread reconcile from its
own loop (removed from ui-new's loop). MessageHistory exposes newest-first
DM ring iteration and a public contactByPrefix().

Verified on L2 hardware: navigation, send/receive, sleep/wake.

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

solo/wio-tracker-l2/platformio.ini

@@ -35,3 +35,32 @@ build_src_filter = ${Wio_Tracker_L2.build_src_filter}
 lib_deps =
   ${Wio_Tracker_L2.lib_deps}
   densaugeo/base64 @ ~1.4.0
+
+; ui-lvgl skeleton: the real L2 interface -- LVGL 9 frontend over the shared UI
+; Core (docs/development/ui-core.md, step 5). Not *_solo_dual yet (no release).
+[env:Wio_Tracker_L2_companion_solo_lvgl]
+extends = Wio_Tracker_L2
+build_flags =
+  ${Wio_Tracker_L2.build_flags}
+  -I examples/companion_radio/ui-lvgl
+  -D DISPLAY_CLASS=WioTrackerL2Display
+  -D UI_ZOOM=1
+  -D LV_CONF_INCLUDE_SIMPLE
+  -D MAX_CONTACTS=350
+  -D MAX_GROUP_CHANNELS=40
+  -D BLE_PIN_CODE=123456
+  -D DUAL_SERIAL=1
+  -D OFFLINE_QUEUE_SIZE=256
+  -D FIRMWARE_SOLO_BUILD=1
+  -D MESHCORE_VERSION='"1.17.1"'
+  -D AUTO_OFF_MILLIS=60000
+build_src_filter = ${Wio_Tracker_L2.build_src_filter}
+  +<helpers/esp32/*.cpp>
+  +<helpers/ui/LGFXDisplay.cpp>
+  +<helpers/ui/MomentaryButton.cpp>
+  +<../examples/companion_radio/*.cpp>
+  +<../examples/companion_radio/ui-lvgl/*.cpp>
+lib_deps =
+  ${Wio_Tracker_L2.lib_deps}
+  densaugeo/base64 @ ~1.4.0
+  lvgl/lvgl @ 9.2.2   ; pinned: bump deliberately, re-test on hardware