ci: 移除 Apple 签名发布流程

[GcsSloop]

变更

• 从 GitHub Actions release workflow 中移除 Apple keychain、certificate import 和 notarization 调用
• 将 CI 的回归脚本替换为禁止 Apple 签名逻辑回到 workflow 的检查
• 标记旧 macOS signing 计划文档为已废弃

验证

• bash scripts/test/desktop_updater_config_test.sh
• bash scripts/test/go_test_with_retry_test.sh
• bash scripts/test/release_no_apple_signing_test.sh
• bash scripts/test/release_updater_signing_key_test.sh
• bash scripts/test/release_version_helpers_test.sh
• bash scripts/test/sync_release_metadata_test.sh
• bash scripts/test/collect_release_assets_test.sh
• bash scripts/test/release_updater_manifest_test.sh
• bash scripts/test/package_local_release_test.sh
• bash scripts/test/release_msvc_spub_test.sh
• bash scripts/test/build_ai_gate_msvc_test.sh
• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/dev-ci.yml"); YAML.load_file(".github/workflows/release.yml")'
• rg Apple signing keywords under .github (no matches)