feat(ui-lvgl): offline raster map from the microSD

Map screen (Home > Map): Web-Mercator tiles from /maps/{z}/{x}/{y}.png on
the card (Meshtastic MUI layout; per-column TPK1 .pak also read), drag to
pan, +/- zoom, re-centre/follow GPS, Nearby nodes with a position as
markers opening node detail. Tiles decode one per loop pass into a
12-slot RGB565 cache in PSRAM. map/TileProvider.h is the swap point for a
later vector renderer: the screen only calls renderTile(). The tile set's
credit line comes from maps/attribution.txt.

L2 mounts the card over SDMMC 1-bit (CLK 2, CMD 3, D0 1). LVGL's lodepng
is enabled; note its LVGL patch returns an lv_draw_buf_t*, not pixels.
LVGL pool 2 MB for PNG decoding. Fonts gain map / users icons.

tools/maps/fetch_tiles.py prepares a card for an area (presets for
Poland), requires an explicit tile URL (tile.openstreetmap.org blocks
offline use) and stops on placeholder images. The LVGL sim preloads
web/maps into the L2's /sdcard and puts its GPS on Kraków.

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

docs/development/ui-core.md

@@ -147,6 +147,7 @@ consumes keys only.
 - Theme tokens (colours, spacing, typography) in one place — the first chance to realise the "Amber Trace" direction in colour.
 - 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.
 - PR #3381's LVGL UI is a reference for platform glue (flush, GT911, PSRAM pool) only; its screens are not adopted.
 
 ## Migration plan