feat(game): add survivor_game with arena and quarter-view camera

Static arena with 20x20 floor and 4 box obstacles rendered using the
forward PBR pipeline with shadow mapping. Fixed quarter-view camera
at (0, 15, 10) looking at origin.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -1877,6 +1877,21 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6637bab7722d379c8b41ba849228d680cc12d0a45ba1fa2b48f2a30577a06731"
 
+[[package]]
+name = "survivor_game"
+version = "0.1.0"
+dependencies = [
+ "bytemuck",
+ "env_logger",
+ "log",
+ "pollster",
+ "voltex_math",
+ "voltex_platform",
+ "voltex_renderer",
+ "wgpu",
+ "winit",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.117"