First attempt at a GPU runner

Currently failing with an error I don't understand:

```
wgpu error: Validation Error

Caused by:
  In Device::create_shader_module, label = '...\image_binary.spv'

Shader '...\image_binary.spv' parsing error: InvalidTypeWidth(1)
```

enkou-shaders/Cargo.toml

@@ -16,8 +16,3 @@ libm.workspace = true
 rand.workspace = true
 rand_xoshiro.workspace = true
 spirv-std.workspace = true
-
-[dev-dependencies]
-anyhow.workspace = true
-image.workspace = true
-tempfile.workspace = true