🎨 Palette: Improve AppDiagnosticsView UX and Accessibility

[emkey1]

💡 What: Enhanced the "Copy Report" button in AppDiagnosticsView.swift by wrapping the copiedReport state toggle in withAnimation blocks, adding a visual checkmark icon, and implementing .accessibilityLabel and .accessibilityHint.

🎯 Why: To provide a graceful visual transition and transient feedback when the diagnostic report is copied, and to ensure the action is clear to VoiceOver users.

📸 Before/After: Visual transitions now fade in/out smoothly instead of popping abruptly, and a checkmark appears for visual confirmation. Screen readers correctly announce "Copy diagnostics report" and "Copied diagnostics report".

♿ Accessibility: Added detailed ARIA equivalents to improve VoiceOver support on the icon and dynamically updating text.

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PR created automatically by Jules for task 9379385691305372279 started by @emkey1

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