ci: complete native ARM64 release coverage

[meop]

Summary

• add a native aarch64-pc-windows-msvc build on windows-11-arm
• use the explicit Intel macOS runner for x86_64-apple-darwin
• run tests for native Windows ARM64 while continuing to skip execution only for cross-compiled Linux ARM targets

Validation

The native Windows ARM64 job built, tested, packaged, and uploaded its artifact successfully:
https://github.com/meop/dust/actions/runs/31940439266/job/95148703970

Disclosure

This change was prepared with assistance from OpenAI Codex. I reviewed the resulting diff and validation results.

[meop]

Validation note: the overall fork workflow is still shown as queued because the existing Build (ubuntu-24.04-riscv, riscv64gc-unknown-linux-gnu) job has not been assigned a runner. All scheduled jobs completed, and the new native Windows ARM64 job passed. The queued RISC-V job was not introduced or modified by this PR.

Overall run: https://github.com/meop/dust/actions/runs/31940439266