App 2.39.0, server 2.7.0: Grid with map

A new Overview style: the Grid over the roads round the car from
OpenStreetMap, drawn in the floor's perspective, heading up, the bigger
roads glowing brighter, the car as a chevron.

Server: POST /v1/map/roads {z:14,x,y} fetches a tile's drivable roads
from Overpass (OVERPASS_URL; one request at a time, at least a second
apart), simplifies them to tile-local points in four classes, caches
them for 30 days and never logs the tile.

App: MapRoads keeps the 3x3 tiles round the car from its own cache or
the server; GPS only while the style is shown; bearing from the GPS or
from successive positions. Without GPS, server or roads the plain floor
says why. OSM attribution on screen and in LICENSE.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6

THEMES.md

@@ -1,6 +1,6 @@
 # Overview styles
 
-The Overview can look seventeen ways: pick one under **Settings → Overview style**. Every style shows
+The Overview can look eighteen ways: pick one under **Settings → Overview style**. Every style shows
 the same readings (battery, range, power, speed, gear, usage, trip, climate, odometer, time) and
 shows "—" for anything the car did not answer, never a made-up zero.
 
@@ -10,7 +10,7 @@ emulator at the car's resolution with **sample values** (87 km/h in D, 76 %, 18.
 emulator has no car; on the car the values are live.
 
 **Colours.** Most styles are drawn in the accent colour you pick from the MG4 paints (Settings →
-Accent colour; shown here in Dynamic Red). Retro, Terminal, Grid and Visor can also show their original
+Accent colour; shown here in Dynamic Red). Retro, Terminal, Grid (with or without the map) and Visor can also show their original
 colours, and Sci-fi, Cartoon, Nixie tubes, Time circuits, Quest and Empire always do; while one of those is shown, the whole app
 (navigation, buttons, switches) takes on its colours too.
 
@@ -29,6 +29,7 @@ colours, and Sci-fi, Cartoon, Nixie tubes, Time circuits, Quest and Empire alway
 | [Nixie tubes](#nixie-tubes) | glowing glass tubes | own |
 | [Chronograph](#chronograph) | a watch face | accent |
 | [Grid](#grid) | neon lines on a glowing grid floor | original or accent |
+| [Grid with map](#grid-with-map) | the Grid, with the real roads round the car on its floor | original or accent |
 | [Time circuits](#time-circuits) | a time machine's LED displays | own |
 | [Quest](#quest) | a fantasy game's interface | own |
 | [Visor](#visor) | a soldier's helmet display | original or accent |
@@ -162,6 +163,20 @@ films' other side.
 ![Grid with the navigation](screenshots/themes/grid-panel.png)
 ![Grid, full screen](screenshots/themes/grid.png)
 
+## Grid with map
+
+The Grid, with the roads round the car from OpenStreetMap laid on its floor as light lanes, in
+the floor's perspective and turned with the direction you drive: motorways glow brightest, then
+main roads, then the smaller streets, fading towards the horizon. The car is the chevron on the
+floor, and between GPS fixes it runs on with the speed. The roads come through the car's own
+server, which fetches them from OpenStreetMap and keeps them (see the README); the car also keeps
+the last few hundred tiles itself. Without GPS, the server or the roads, the floor says so and
+stays the plain grid. The light-cycle trail makes way for the map here; power stays on the disc.
+Shown with sample values over real roads in central Berlin.
+
+![Grid with map, with the navigation](screenshots/themes/grid-map-panel.png)
+![Grid with map, full screen](screenshots/themes/grid-map.png)
+
 ## Time circuits
 
 After the time machine in Back to the Future: three rows of LED read-outs in a metal panel,