Replaces the inline color-only demo_tilemap with a dep on the
prototype-fa-starter asset lib and its baked fa_terrain_v1 atlas.
The map atlases[] alias-string is updated to fa_terrain_v1; the
packed-u32 layer-tiles keep their numeric values because the baker
assigned the expected IDs (1 for grass_field surface tile, 2 for
stone_wall_brick wall tile). Adds maps.load_textures() call in init.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Surface + wall layers with entity slot between them. Uses
maps.draw_map_pre_entities and maps.draw_map_post_entities so character
sprites render between surface and wall layers.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
