Refactor menu rendering and improve projection sampling

- Updated AsciiRasterizer to support game and episode selection menus with improved layout and cursor handling.
- Enhanced SixelRasterizer and SoftwareRasterizer to modularize menu drawing logic for game and episode selection.
- Introduced new methods for drawing menus and applying fade effects across rasterizers.
- Adjusted wall texture sampling in Rasterizer to anchor to projection height center for consistent rendering.
- Added tests for wall texture sampling behavior to ensure legacy compatibility and new functionality.
- Modified Flutter audio adapter to use nullable access for active game and adjusted game selection logic in the main class.
- Cleaned up input handling in Wolf3dFlutterInput by removing unused menu tap variables.

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

packages/wolf_3d_dart/test/engine/audio_events_test.dart

@@ -147,7 +147,7 @@ WolfEngine _buildEngine({
     startingEpisode: 0,
     frameBuffer: FrameBuffer(64, 64),
     input: input,
-    audio: audio,
+    engineAudio: audio,
     onGameWon: () {},
   );
 }