🎨 Palette: [UX improvement] NWS Alerts accessibility

[d3mocide]

💡 What: Added aria-expanded, aria-controls, and focus-visible styling to the NWS Alerts dropdown button.
🎯 Why: Screen readers were unable to announce the toggle state of the alerts menu, and keyboard users could not see when the button was focused.
📸 Before/After: Visual change is the addition of an amber focus ring when tabbing via keyboard.
♿ Accessibility: Bound aria-expanded to component state, linked aria-controls to a new ID on the content container, added aria-label, and applied outline-none with focus-visible:ring-1 focus-visible:ring-amber-400.

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PR created automatically by Jules for task 9227779397281958312 started by @d3mocide

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