Stabilize Windows CI build by switching to xmake-pack workflow path

[Copilot]

build-windows failed in Actions run 36187019268 because the workflow used the legacy build.ps1 path, which hit an xmake tool-resolution failure (cannot get program for mrc) before producing artifacts. This change aligns Windows with the xmake-native packaging flow already used cross-platform.

• Root-cause correction

  • Replaced Windows build.ps1 + manual Copy-Item artifact assembly with direct xmake pack packaging.
  • Removes dependency on the failing legacy invocation path that triggered mrc resolution errors.

• Workflow normalization

  • Standardized Windows/Linux/macOS build jobs on:
    • xmake-io/github-action-setup-xmake@v1
    • xmake-version: 3.1.1
    • xmake pack for release/debug outputs
  • Updated artifact upload/download action versions and paths to match build/xpack/doorstop/*.zip outputs.

• Artifact compatibility

  • Kept collect-stage rename/version logic intact so downstream release zip naming remains unchanged.

- name: Setup xmake
  uses: xmake-io/github-action-setup-xmake@v1
  with:
    xmake-version: 3.1.1

- name: Build Release
  run: xmake pack

- name: Build Debug
  run: |
    xmake f -m debug
    xmake pack