feat(02-05): EventDetailPopover read-only popover, XSS-safe, wired into CalendarShell

- EventDetailPopover: reads openEventId from Zustand, resolves occurrence from TanStack Query cache
- Dual-mode: standalone (Zustand-driven) + customComponents.eventModal (Schedule-X)
- Plain-text JSX children for all event fields (T-02e-01 XSS guard)
- Focus trap, Escape to close, backdrop-click to close, aria-label=Close (44px target)
- Phone: bottom sheet layout; tablet/desktop: centered popover (max-width 360px)
- Phase-3 footer action area reserved with comment
- CalendarShell: passes customComponents.eventModal=EventDetailPopover to ScheduleXCalendar
- test-setup.ts: import @testing-library/jest-dom for toHaveTextContent matcher
- All 36 tests pass, tsc clean

apps/pwa/src/test-setup.ts

@@ -10,6 +10,9 @@
  *     from viewport width at store initialisation time.
  */
 
+// Extend Vitest's expect with jest-dom matchers (toHaveTextContent, etc.)
+import '@testing-library/jest-dom'
+
 // Polyfill window.matchMedia for jsdom.
 // jsdom does not implement the CSSOM MediaQueryList API.
 // calendarStore.ts calls window.matchMedia during Zustand create(), so this