feat(ui-lvgl): pick download areas with a frame, list of map areas

- Download an area: a frame with four corner handles on the map (kept in
  world coordinates, the map pans / zooms under it); a bar gives its size,
  zoom range, tile count and size, the trails switch and Get; areas on the
  card are outlined
- Map tools > Map areas: the downloaded areas (map/AreaStore.h,
  /sdcard/maps/areas.txt) -- show (framed, outlined), rename, fill gaps,
  refresh (force re-download), trails on / off, delete (in steps, keeping
  tiles another area covers)
- TileDownloader: force and per-job trails options

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

docs/development/l2-roadmap.md

@@ -245,8 +245,12 @@ Ideas to come back to (2026-09-26):
       over the base map (Map tools > Hiking trails); fetched with an area
       download (re-running one adds just the trails) and live; empty tiles
       as 0-byte files.
-- [ ] Area manager: named list of downloaded areas (regenerate, delete),
-      a draggable frame to pick an area instead of the visible screen.
+- [x] Map areas: a frame with corner handles picks the area to download
+      (the map pans / zooms under it; size, zoom range, tiles, trails in a
+      bar); downloaded areas are listed in /sdcard/maps/areas.txt (Map tools
+      > Map areas: show, rename, fill gaps, refresh, trails on / off, delete
+      -- tiles another area covers stay). Maps fetched before the list aren't
+      in it (re-download them).
 - [x] A grid under the map (and the minimap), its step a round distance in
       the metric / imperial unit, with a scale bar: position and scale where
       no tile is loaded.