feat(02-05): ColorLegend, AppNav, ViewToolbar, SkeletonCalendar, EmptyState; retire EventProof

- ColorLegend: per-member color swatches (12px circle, label) + always-visible Family row
- AppNav: phone 48px top bar (avatar with aria-label/title) + tablet/desktop 240px sidebar with ColorLegend
- ViewToolbar: Today/prev/next + Day/Week/Month/Agenda view switcher; 44px min-height; active state uses surface tint not accent
- SkeletonCalendar: shimmer month (6x7 grid) and agenda (4 date-group blocks) variants; aria-busy=true
- EmptyState: CalendarDays icon + 'Nothing here' heading + body copy per UI-SPEC
- CalendarShell: full phone/desktop layout with AppNav + ViewToolbar + ColorLegend chrome
- CalendarShell: state branches — loading→SkeletonCalendar, empty→EmptyState, error→'Couldn't load events' + Retry button (refetchQueries)
- EventProof.tsx deleted; legacy types removed from client.ts
- CalendarShell.test.tsx: updated to waitFor ScheduleXCalendar after data loads
- All 36 tests pass, tsc clean, vite build clean (490kB)

apps/pwa/src/components/CalendarShell.test.tsx

@@ -152,9 +152,10 @@ describe('CalendarShell — CAL-03 render smoke', () => {
     expect(() => renderWithClient(<CalendarShell />)).not.toThrow()
   })
 
-  it('mounts the ScheduleXCalendar with a non-null calendarApp', () => {
+  it('mounts the ScheduleXCalendar with a non-null calendarApp after data loads', async () => {
     renderWithClient(<CalendarShell />)
-    const calEl = screen.getByTestId('schedule-x-calendar')
+    // CalendarShell shows SkeletonCalendar during loading; wait for data to resolve
+    const calEl = await screen.findByTestId('schedule-x-calendar')
     expect(calEl).toBeDefined()
     expect(calEl.getAttribute('data-has-app')).toBe('true')
   })