Build the patched WINQ-EMU runtime from source in CI

[btsouth]

The GPU path currently downloads a third-party alpha binary bundle.

Pin the source and patch revisions, build the Windows runtime reproducibly in CI, verify its contents, publish the matching source and licenses, and feed the resulting archive into the existing signed-manifest chain. Upstreaming the WHPX patches remains the preferred long-term result.

[btsouth]

The pinned source build, matching source archive, licenses, manifests, and CI workflow are now implemented in 521511c. The workflow is green. Keeping this open until the rebuilt runtime passes the AMD, Intel, and NVIDIA hardware matrix and replaces the current production pin.

[btsouth]

The source-built runtime and matching source archive now ship in v0.0.11-preview. Keeping this open for recorded AMD, Intel, and NVIDIA validation on the shipped runtime, tracked with #10.