feat: multiple map tile styles switchable in Settings > Interface

New src/mapStyles.ts defines five styles from bincio_planner's sources:
- Liberty (OpenFreeMap vector, default)
- CyclOSM (cycling infrastructure raster)
- Topo (OpenTopoMap elevation raster)
- Satellite (Esri World Imagery raster)
- OSM (standard raster fallback)

Raster sources are wrapped in a StyleSpecification so MapLibre handles
them natively. Setting persisted via ThemeContext (AsyncStorage key
mapTileStyle). RecordingScreen and ActivityDetailScreen both read from
context so the style updates everywhere simultaneously.

MAP_STRATEGY.md added (untracked) with full map roadmap.

.gitignore

@@ -39,3 +39,4 @@ yarn-error.*
 # generated native folders
 /ios
 /android
+MAP_STRATEGY.md