[iOS][macOS] Remove iOS Xcode Project

[mischreiber]

Platforms Impacted

• iOS
• visionOS
• macOS

Description of changes

Use SPM exclusively for consuming Fluent within our macOS and iOS demo apps.

A side-effect of this change is a major overhaul of how our library interacts with Xcode. In particular:

• The FluentUI iOS Xcode project has been completely removed.
• The workspace that wrapped the iOS library and demo app has been removed.
• The macOS Xcode project has had the library target removed.

Both demo app projects (macOS and iOS) will now consume the FluentUI library directly via Swift Package Manager. This will facilitate upcoming refactors to make it easier to share code between iOS and macOS.

Binary change

The current system for measuring binary impact is no longer valid, since there will no longer be a discrete libFluentUI.a created as part of the build process. I'm currently exploring newer approaches to measure binary impact.

Verification

Extensive sanity passes of both macOS and iOS test apps confirm no loss of functionality.

Tests included:

• SwiftUI components
• AppKit/UIKit components
• Components that load image resources (e.g. Avatar)
• Objective-C demos

Visual Verification

Before	After
Screenshot or description before this change	Screenshot or description with this change

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

[mischreiber]

Confirmed through testing in a few apps that this should represent a <10kB binary increase across the board.