IOS-5566 Disable Space Hub animation on first load and when off-screen

[ignatovv]

Summary

• Wait for chat message previews before showing spaces to prevent jumping on first load
• Disable animations when Space Hub is off-screen so returning shows spaces in correct order without animation

[claude]

Best Practices

SpaceHubList.swift:35
Wrapping in DispatchQueue.main.async is unnecessary since SwiftUI views are already @mainactor. This should be:

.onAppear { model.animationsEnabled = true }

The flag will still be set on the main thread, but synchronously during the appear lifecycle event.

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⚠️ Minor Issues - Remove unnecessary DispatchQueue.main.async wrapper