Delete all map files and mapinfo.lua files

Removed:
- test-engine/maps/sb_initial_blank_10x8.sdz (generated map)
- test_fixtures/minimal_test_map.sdd/mapinfo.lua
- test-engine/games/test_blank.sdd/ (entire directory)

No map files, no mapinfo.lua files, no map folders remain.
test-engine/maps/ directory is now empty.

Author: claude