This performs various upgrades and fixes:
- Use lossless compression for all textures to improve quality and fix
textures on the web export. Textures are very small in size, so they didn't
use much memory in the first place anyway.
- Adjust the appearance when running under the Compatibility rendering method
(including the web export), so that the scene brightness roughly matches
Forward+.
- Enable physics interpolation for smoother visuals when the rendering
FPS doesn't match the physics tick rate (60 in this project).
- Switch the physics engine to Jolt Physics for faster, more reliable physics.
- Use the `canvas_items` stretch mode to scale 2D elements automatically.
- Remove redundant CanvasLayer node for the HUD (not needed in 3D games).
- Tweak the HUD to constrain the coin display to a 16:9 aspect ratio, so that
the coin display isn't too far away on ultrawide displays.