Support universal builds

[CraigSiemens]

No description provided.

[Copilot]

Pull Request Overview

This PR refactors the Xcode version management system to support universal builds by restructuring the API models and filtering releases based on architecture compatibility.

Key changes:

• Restructured API response models to include architecture information
• Added architecture detection and filtering for download compatibility
• Added a prefer-universal flag to prioritize universal builds

Reviewed Changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Sources/XcodeVersionManager/Models/XcodeReleasesAPI.swift	New API client with enhanced response models including architecture support
Sources/XcodeVersionManager/Models/XcodeReleases.swift	Removed old API implementation
Sources/XcodeVersionManager/Models/XcodeRelease.swift	New domain model with architecture and OS version requirements
Sources/XcodeVersionManager/Models/CalendarDate.swift	New date model for release dates
Sources/XcodeVersionManager/Models/Architecture.swift	New architecture detection and enumeration
Sources/XcodeVersionManager/Commands/ListCommand.swift	Updated to use new API and added known releases subcommand
Sources/XcodeVersionManager/Commands/DownloadCommand.swift	Added architecture filtering and universal build preference
Sources/XcodeVersionManager/Commands/Arguments/InstalledXcodeVersion.swift	Updated completion handler signature
Package.swift	Updated dependency to use semantic versioning

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