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

k8s/server.yaml

@@ -50,6 +50,9 @@ spec:
               value: https://git.stinnesbeck.com
             - name: FORGE_REPO
               value: nils/mg4
+            # The roads for the app's Grid map, from OpenStreetMap; "off" switches maps off.
+            - name: OVERPASS_URL
+              value: https://overpass-api.de/api/interpreter
             - name: INFLUX_TOKEN
               valueFrom:
                 secretKeyRef: