Action Version Updates

• actions/checkout: v4 → v5
• actions/setup-dotnet: v4 → v5
• cake-build/cake-action: master → v3.0.1
• CodeQL actions: v2 → v4

Build Matrix Changes

• Remove: macos-13 (deprecated)
• Add: macos-15-intel and macos-latest runners
• Maintain existing windows-latest and ubuntu-latest