Add minimal SMF map fixture and update gitignore

- Add properly formatted minimal 128x128 Spring Map File (SMF)
  - Correct header with magic "spring map file\0"
  - Proper constraints: mapx/mapy divisible by 128, squareSize=8,
    texelPerSquare=8, tilesize=32
  - Includes heightmap, typemap, minimap, metalmap, feature data

- Update .gitignore to exclude test engine artifacts:
  - test-engine/maps/, infolog.txt
  - Root-level /games/ and /script.txt (accidentally created during testing)

Note: Map still causes segfault at texture loading due to missing
DXT1-compressed .smt tile files. Creating these requires image processing
tools (PIL/libsquish/nvdxt) not available in environment.

Author: claude

.gitignore

@@ -13,5 +13,11 @@ env/
 
 # Test engine artifacts
 test-engine/games/
+test-engine/maps/
 test-engine/script.txt
+test-engine/infolog.txt
 test-engine/test-data/
+
+# Root-level test artifacts (accidentally created during testing)
+/games/
+/script.txt