feat!: implement proper error handling, drop most expect() & unwrap() usages

tests/game.rs

@@ -3,7 +3,7 @@ use pacman::map::Map;
 
 #[test]
 fn test_game_map_creation() {
-    let map = Map::new(RAW_BOARD);
+    let map = Map::new(RAW_BOARD).unwrap();
 
     assert!(map.graph.node_count() > 0);
     assert!(!map.grid_to_node.is_empty());
@@ -16,6 +16,6 @@ fn test_game_map_creation() {
 #[test]
 fn test_game_score_initialization() {
     // This would require creating a full Game instance, but we can test the concept
-    let map = Map::new(RAW_BOARD);
+    let map = Map::new(RAW_BOARD).unwrap();
     assert!(map.find_starting_position(0).is_some());
 }