tile.id is now an integer; the stable string identifier is tile.name.
Updates all tile-record string-id assertions to use .name. Adds
walkable field to stub atlas JSONs so gameplay assertions pass without
the legacy tiles dir. Test bootstrap calls maps.load_textures with
aliases pointing to the test-lib itself as the asset provider. Moves
load_textures calls inline after each set_current (Task 4 and Task 9
blocks) so all tile-record shape and walkability checks use atlas
records throughout. Bumps version to 0.3.0, dep on maps 0.3.0.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
