Platforms Impacted

• iOS
• visionOS
• macOS

Description of changes

Creates a new extension on NSColor that adds dynamic color support, similar to the equivalent methods in UIColor+Extensions.swift.

These changes will be important for FluentTheme integration, which is almost ready :)

New:

• Create an NSColor with explicit light and dark variants.
• Fetch these values back on demand.
• Add test UI to the demo app to validate this.

Verification

Verified that the new dynamic colors work as expected:

• The light method always returns the light value.
• The dark method returns either dark if it exists, or light if not.
• Otherwise, the color will draw according to the current NSAppearance as expected. This includes redrawing when the system appearance changes.

Visual Verification

Before	After

Pull request checklist

This PR has considered:

• Light and Dark appearances
• iOS supported versions (all major versions greater than or equal current target deployment version)
• VoiceOver and Keyboard Accessibility
• Internationalization and Right to Left layouts
• Different resolutions (1x, 2x, 3x)
• Size classes and window sizes (iPhone vs iPad, notched devices, multitasking, different window sizes, etc)
• iPad Pointer interaction
• SwiftUI consumption (validation or new demo scenarios needed)
• Objective-C exposure (provide it only if needed)

Microsoft Reviewers: Open in CodeFlow