🎨 Palette: Multi-sensory feedback for copy/paste actions

[emkey1]

💡 What: Added visual transient text ("Copied!" / "Pasted!"), a haptic success vibration, and a VoiceOver announcement to the TerminalSelectionMenuView copy and paste buttons.
🎯 Why: Clipboard operations are typically silent actions. This multi-sensory feedback ensures users—including those relying on screen readers or physical feedback—are confident their action succeeded without needing to manually verify the clipboard.
📸 Before/After: Visual transitions now cross-dissolve to confirm actions for 1.5s.
♿ Accessibility: Uses UIAccessibility.post(notification: .announcement) to provide non-visual confirmation for VoiceOver users, addressing a critical accessibility gap for transient visual states.

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PR created automatically by Jules for task 12022058812874968080 started by @emkey1

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