🎨 Palette: Improve accessibility of AI Analyst Panel buttons

[d3mocide]

💡 What: Added aria-label and aria-expanded attributes, as well as focus-visible styling to the "Settings" and "Close" buttons in the AI Analyst Panel widget.
🎯 Why: Icon-only buttons without proper ARIA labels are inaccessible to screen readers. Adding focus-visible ensures users navigating via keyboard can clearly see which interactive element has focus.
♿ Accessibility:

• Added aria-label to Settings and Close buttons.
• Added aria-expanded to the Settings button to communicate the dropdown state.
• Added focus-visible:ring-1 focus-visible:ring-violet-400 outline-none to improve keyboard navigation visibility, matching the widget's theme color.

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PR created automatically by Jules for task 16736053710257908665 started by @d3mocide

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