feat: Add core map generation and management system

- Introduced MapData, MapGenerator, and MapPainter classes for procedural map generation.
- Implemented LevelManager to handle level initialization and navigation.
- Created TurnManager for managing turn order in a turn-based system.
- Added Player and Enemy character classes with movement and turn-taking capabilities.
- Established pathfinding using AStar2D in PathfindingHandler.
- Integrated new scenes for player and enemy characters, along with world setup.
- Included a new tileset for futuristic Zelda-themed assets.

map/tile.gd

@@ -0,0 +1,8 @@
+## Tile.gd
+# Resource representing a single tile in the map.
+# Used for storing tile properties such as walkability.
+class_name Tile
+extends Resource
+
+# Whether this tile can be walked on (used for pathfinding).
+var is_walkable: bool = false