- Notifications ✅ split: the Core decides *what* happened (`MessageArrived` with kind / DM sender / channel slot, `AdvertHeard`); the frontend decides *how* to show it (`showAlert`, `SoundNotifier`, vibration, LED, wake-on-message) — those are platform services.
- Fonts ✅ Noto Sans generated by `ui-lvgl/fonts/generate.sh` (lv_font_conv): European Latin (Latin-1, Extended-A/B), Greek, Cyrillic + supplement, typographic punctuation, currency, LVGL symbols; 12/14/16/20 px, clock 40 px digits only. On-screen keyboard (`ui-lvgl/Keyboard.h`), phone-style: one layout per script (Latin QWERTY / Cyrillic ЙЦУКЕН / Greek) chosen by the same `keyboard_main_alphabet` / `keyboard_alt_alphabet` prefs as `ui-new` (globe key switches), hold a key for its variants; compose limit counted in UTF-8 bytes. Long-press variants and UTF-8 case mapping are shared with `ui-new` in `ui-core/KeyboardData.h`.
- Simulator ✅: `SIM_UI=lvgl variants/sim/build_wasm.sh` builds the same `ui-lvgl` code for the browser (`SimLcdDisplay` in `variants/sim/SimDisplayDriver.h` blits LVGL's RGB565 flush to a 320×240 canvas; the `SIM_PLATFORM` branch of `ui-lvgl/LvglPort.h` feeds the mouse in as touch). LVGL comes from the L2 env's PlatformIO libdeps; its objects are cached in `web/build/obj_lvgl/`. `web/lvgl.html` runs it next to a `ui-new` peer on a direct link (buttons: advert, peer DM, peer → Public, the board button) and exposes `window.sim` (`tap`, `hold`, `touch`, `peerDM`, `peerChannel`) for headless checks.
- Map (in progress): offline Web-Mercator raster tiles on the microSD (`/maps/{z}/{x}/{y}.png`, the Meshtastic MUI layout; optional per-column `.pak` from PR #3381's packer), SDMMC 1-bit mount in `LvglPort.h`. `ui-lvgl/map/TileProvider.h` is the swap point: the screen and `map/TileCache.h` (12 decoded RGB565 tiles in PSRAM, LRU) only call `renderTile(z, x, y, rgb565)`, so a vector renderer can replace the PNG provider later. `MapScreen.h`: pan by drag, +/-, re-centre/follow GPS, Nearby nodes with a position as markers (tap = node detail), one tile decoded per loop pass. `maps/attribution.txt` is shown on the map. Planned split (user, 2026-09-25): a Nodes map (every contact with a position) and a separate Navigation map (waypoints + live shares only, for walking to a target). Tiles come from `tools/maps/fetch_tiles.py` (no default server: tile.openstreetmap.org blocks offline use) or, next, an on-device WiFi download of the visible area.
1.**Skeleton** ✅. `examples/companion_radio/ui-core/` with `UiCore.h` (facade), `MessageHistory.h`, `DmUnreadTable.h`. Header-only for now, reached from `ui-new/UITask.cpp` by relative include, so none of the 66 variant `platformio.ini` files that build `ui-new` change. `UITask` heap-allocates one `UiCore` in `begin()` (before the screens, as `MessagesScreen` used to own the history on the heap); `MessagesScreen` binds to `core().history` by reference. When the Core grows real `.cpp` files, compile them through a unity `.cpp` inside each frontend directory.
2.**Engines, one per commit.** Clock tools ✅ (also introduced `ui-core/UiEvents.h`, the Core → frontend event queue; `UITask::tickCore()` runs `UiCore::loop()` and drains it) → ping ✅ → course-over-ground ✅ → live share ✅ → locator ✅ → trail ✅ → notifications ✅ (with step 3). `UITask` shrinks to screen management + drawing.
3.**Flip the interface** ✅. `UiCore` is `MyMesh::Listener`; `ui-new`'s `UITask` derives `UITaskBase` + `UiCoreHost` and is fed by events, drained at the start (mesh-originated) and end (engines) of its `loop()`. Mesh callbacks no longer touch the display or buzzer directly.
6. Contacts/Nearby, Admin, Bot logic extraction as the LVGL screens for them are built. Nearby ✅: `ui-core/NearbyModel.h` builds the list (contacts + live [LOC] shares + heard adverts, or scan results), filter and sort; `ui-new`'s `NearbyScreen` inherits it (entry array stays with the screen), `ui-lvgl` owns one for its Nearby list + node detail (Message, Ping, favourite, Add, Delete). Home became three tiles: Messages, Nearby, Settings.
