## What changed
- Add explicit x64 and ARM64 targets for native builds, runtime preparation, and linking using the existing voice recipes. Each target requires native Windows execution of the matching architecture.
- Declare compiler, SDK, Python, and CMake inputs; require an explicitly supplied Cygwin/pkgconf tool tree and a fixed `SystemRoot`. Validate installed tool selections against the manifest and declared files.
- Pair Windows DLLs with SDK import libraries, preserve plugin and receipt runfiles, and omit Unix runtime-search flags. Use Python for portable payload copying.
- Correct the MSVC ARM64 tool directory casing to `HostArm64` and document provisioning and build commands.
The generic Rust-consumer aliases remain separate; native Windows Bazel execution and consumer validation are still needed to establish complete Windows voice support.
## Testing
Add eight unit tests covering tool selection, path anchoring, invalid inputs, and DLL/import-library copying, plus x64 and ARM64 link smoke targets that reference `gst_version`.
GitOrigin-RevId: fb2b4998e9ffb5b64ca830ebf4bb4633fc959eb9
## Why
The MSVC runtime and Windows SDK repositories discard their tool binaries during setup, leaving native build tools unavailable to Bazel consumers.
## What changed
Patch `windows_support` to retain native MSVC tools and support files, plus the selected SDK's versioned tools, for `x64` and `arm64`. Expose them through opt-in `msvc_tools_x64`, `msvc_tools_arm64`, `winsdk_tools_x64`, and `winsdk_tools_arm64` directory targets.
Exclude the retained tool trees from the existing `sysroot_files`, `headers`, and `libs` targets.
GitOrigin-RevId: df7db08fecfb5e389252332842b8d7361d166891
