v0.0.2

Fixed

• capture internal errors from shader compilers; from_device returns Result
• (shader) no discard inside shade_pbr (FXC: not all control paths return)
• serialise wgpu instance/adapter/device creation; skip GPU tests on software adapters

Changed

• GpuRenderer::from_device now returns Result<Self>: pipeline
  creation runs under validation + internal error scopes, so a shader
  the backend compiler rejects becomes Error::Backend instead of a
  panic in wgpu's default error handler (also for GpuPathTracer).

Fixed

• D3D12 / FXC: shade_pbr no longer discards inside a helper
  function ("not all control paths return a value").