🎨 Palette: Add dynamic aria-label to notification bell

[vireapp]

💡 What: Added a dynamic aria-label to the NotificationBell icon-only button that updates based on the current number of unread alerts. Added an entry to .Jules/palette.md noting the importance of dynamic labels for state-aware buttons.
🎯 Why: Screen reader users previously had no context on the status of their notifications since the button lacked an accessible name, and the state change (pulsing dot) was strictly visual.
♿ Accessibility: Improves experience for assistive technology by explicitly announcing the unread count (e.g., "Notifications, 3 unread") vs just "Notifications" when zero.

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PR created automatically by Jules for task 6723226678166038017 started by @vireapp

[google-labs-jules]

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