ci(release): drop macos-x64 from release matrix

[Sun-sunshine06]

Summary

Temporarily remove macos-x64 from the release matrix.

Why

The Intel macOS runner queue is chronically unavailable for this repo right now, which blocks the whole release pipeline because publish waits for the full build matrix to finish.

Notes

• macos-arm64, windows, ubuntu, and snap remain unchanged.
• I already used this branch's workflow to re-dispatch the v0.1.4 release so the current packaging run can finish without waiting on macos-x64.

[github-actions]

Findings

• [Major] Removing macos-x64 drops a documented supported release artifact — the new build matrix now publishes only the Apple Silicon DMG, so the next GitHub Release will have no installer for Intel Macs. That is a user-visible support regression, not just a CI optimization: the repo still documents open-codesign-*-x64.dmg as the Intel macOS installer in README.md:151, README.zh-CN.md:149, and website/quickstart.md:33, and website/faq.md:86 still lists Intel macOS as supported. CHANGELOG.md:48 also records the earlier fix to ship a correct x64 DMG. Evidence in this PR: .github/workflows/release.yml:129.
  Suggested fix:

  # Keep Intel packaging non-blocking instead of removing it from releases.
  build-macos-x64:
    name: Build (macos-x64, best-effort)
    needs: [gate, changelog]
    runs-on: macos-13
    continue-on-error: true
    steps:
      # same checkout / setup / install / build steps as the main build job
      - run: pnpm --filter @open-codesign/desktop exec electron-vite build
      - run: pnpm --filter @open-codesign/desktop exec electron-builder --mac --x64 --publish never

Summary
Review mode: initial
One major regression found: this PR stops shipping the Intel macOS installer while the project still advertises Intel support. If Intel support is being intentionally dropped, that contract change needs to be made explicit in the docs/site/release messaging in the same PR instead of silently disappearing from the release matrix.

Testing
Not run (automation)

open-codesign Bot

[github-actions]

[Major] This matrix now removes the only macos-x64 release artifact. The repo still advertises Intel macOS support in README.md:151, README.zh-CN.md:149, website/quickstart.md:33, and website/faq.md:86, so this is a release-support regression rather than just a CI optimization.

Suggested fix:

build-macos-x64:
  name: Build (macos-x64, best-effort)
  needs: [gate, changelog]
  runs-on: macos-13
  continue-on-error: true
  steps:
    - run: pnpm --filter @open-codesign/desktop exec electron-vite build
    - run: pnpm --filter @open-codesign/desktop exec electron-builder --mac --x64 --publish never