fix(02): wire calendar-controls plugin and Zustand selectors

Bug A — navigation no-op: replace $app.calendarState private-API poking
with the official @schedule-x/calendar-controls plugin. CalendarShell
creates the plugin once via useState stable initialiser and passes it to
ViewToolbar as `controls`. ViewToolbar calls controls.setDate(PlainDate)
and controls.setView(id) for all navigation and view-switching. Step size
matches the active view: day→±1 day, week→±1 week, month-*→±1 month.

Bug B — popover-open calendar flash: replace the unselected
useCalendarStore() destructuring in CalendarShell and ViewToolbar with
per-field selectors. Neither component now subscribes to openEventId, so
popover open/close no longer triggers a re-render that rebuilds the
Schedule-X config.

- Add @schedule-x/calendar-controls@4.6.0 dependency
- Update CalendarShell.test.tsx: add vi.mock for calendar-controls
- typecheck, vitest (37/37), build all pass

apps/pwa/package.json

@@ -12,6 +12,7 @@
   },
   "dependencies": {
     "@schedule-x/calendar": "4.6.0",
+    "@schedule-x/calendar-controls": "4.6.0",
     "@schedule-x/event-modal": "4.6.0",
     "@schedule-x/events-service": "4.6.0",
     "@schedule-x/react": "4.1.0",