feat(ui): add ConfirmationPopover component for inline confirmations

- Add new ConfirmationPopover wrapper component in shared-ui
- Uses portal pattern to escape overflow constraints
- Supports danger/warning/info variants with appropriate styling
- Uses elevation-3 for proper layering above overlays
- Integrate in QuickEventOverlay for delete confirmation
- Fix parseISO bug in QuickEventOverlay (was not imported)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/shared-ui/src/index.ts

@@ -45,6 +45,9 @@ export { ContactAvatar, ContactBadge, ContactSelector } from './molecules';
 // Layout
 export { ModalFooter, DataCard, PageHeader, KeyboardShortcutsPanel } from './molecules';
 
+// Confirmation (inline popover)
+export { ConfirmationPopover } from './molecules';
+
 // Organisms
 export { Modal, ConfirmationModal, FormModal, AppSlider } from './organisms';
 export type { AppItem } from './organisms';