597cfb9573
The notification dropdown was at z-index: 100, well below fullscreen terminals (1000), modal overlays (1000), and dialog overlays (1000). Because .notification-center creates a stacking context with no explicit z-index, the dropdown was trapped behind any of those overlays and became unclickable. - Set .notification-center z-index to 9999 so it competes above all other overlays in the root stacking context. - Set .notification-dropdown z-index to 9999 for consistency. Quality gates: tsc --noEmit (pass), build (pass)