[Xcode 27] Capture state as weak before any uses

[eschwieb]

The code was capturing state as weak after already using it, and Xcode 27 now complains of the mixed strong and weak usage. Move the capture up to the HStack itself rather than in the ForEach of the stack's buttons, and use it appropriately inside.

Platforms Impacted

• iOS
• visionOS
• macOS

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Binary change

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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)

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