feat: water rendering (#13)

* refactor: update water texture

* feat(gameplay): implement transparent block rendering with depth sorting

* fix(world): use camera pos for distance calculations, make water passable

* refactor(player): use ivec3 for block pass check

* feat(camera): add underwater detection

* feat(renderer): add underwater effect with framebuffer post-processing

* feat(block): add gas property and refactor solid block check

* fix(assets): set leaf block transparency to false

* fix(block): set leaf as transparent

assets/data/block/air.toml

@@ -1,5 +1,6 @@
 id = 0
 is_cross_plane = false
+is_gas = true
 is_liquid = false
 is_passable = true
 is_transparent = true