Stacking every active banner vertically ate header height when several
were active at once. Only the highest-priority banner renders now; a
‹ 1/N › pager cycles through the rest, and all active banners are still
recorded in the notification-center history so cycled-away ones stay
reachable. Newly registered banners preempt the displayed one only when
they outrank it.
Also fix the startup flow: the restart-required banner (now priority 80)
outranks the model-folders setup warning (60), and the setup banner is
retired once a non-empty folder path is saved.
New banners.pager.* keys translated in all 9 locales.
- Replace all remaining 'transition: all' with specific token-based transitions
- Replace 80+ hardcoded box-shadow rgba values with semantic tokens
- Add new tokens: --shadow-side, --shadow-elevated, --shadow-dialog, --shadow-inset-top
- Update dark theme overrides for new shadow tokens
- 32 files changed, net +8 lines (more consistent, less duplication)