🎨 Palette: Added ARIA labels to icon-only buttons

[vireapp]

💡 What: Added missing aria-labels to various icon-only Button and button components.
🎯 Why: Without text content, icon-only buttons need an aria-label attribute to properly describe their action to assistive technologies like screen readers, which is a critical accessibility requirement.
♿ Accessibility:

• Added to room-client-v2.tsx: close mobile tab, open mobile menu, copy room code, and close people overlay buttons.
• Added to video-grid.tsx: mute/unmute microphone, turn camera on/off, and share screen buttons.

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PR created automatically by Jules for task 2816930582782207793 started by @vireapp

[google-labs-jules]

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