Enhanced Notification System

What: Replaced simple single-notification system with a sophisticated priority-based queue.

Details:

• Four priority levels: immediate (0), high (1), medium (2), low (3)
• Notifications queued and displayed based on priority sorting
• "Immediate" priority can interrupt currently displayed notifications
• State structure: { current: notification | null, queue: notification[] }
• Notifications support rich content via jsx property for React components
• Unique key property for deduplication
• Visual theming via color property
• Default 8000ms timeout (configurable via timeoutMs)
• Evidence: Priority queue function Qz() at line 363067, priority sorting F19() at line 363140, priority mapping at line 363139