Improve UX with navigation, attendance management, and calendar fixes

## Quick Wins
- **AdminSidebar**: Move "View Public Site" to clickable logo area
- **Plans**: Fix layout to center single plan, dynamic grid for multiple
- **AdminGallery**: Add empty state message with "Create Event" button

## Event Attendance Enhancement
- **NEW: AdminEventAttendance page** with full-featured table view:
  - Tab filters (All/Yes/No/Maybe RSVPs)
  - Search by name/email
  - Bulk selection with Select All
  - Individual attendance toggle buttons (merged column)
  - CSV export functionality (client requirement)
  - Summary statistics cards
- **AdminEvents**: Navigate to new attendance page instead of dialog
- **App.js**: Add /admin/events/:eventId/attendance route

## Calendar Fixes
- **MemberCalendar**: Add state management for navigation (date/view)
  - Fix non-functional buttons (Today/Back/Next/Month/Week/Day/Agenda)
  - Add onNavigate and onView handlers
- **NEW: MemberCalendar.css**: Extract styles from broken jsx syntax
  - Fix toolbar button styling and interactivity

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

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

src/App.js

@@ -23,6 +23,7 @@ import AdminMembers from './pages/admin/AdminMembers';
 import AdminPermissions from './pages/admin/AdminPermissions';
 import AdminRoles from './pages/admin/AdminRoles';
 import AdminEvents from './pages/admin/AdminEvents';
+import AdminEventAttendance from './pages/admin/AdminEventAttendance';
 import AdminValidations from './pages/admin/AdminValidations';
 import AdminPlans from './pages/admin/AdminPlans';
 import AdminSubscriptions from './pages/admin/AdminSubscriptions';
@@ -218,6 +219,13 @@ function App() {
               </AdminLayout>
             </PrivateRoute>
           } />
+          <Route path="/admin/events/:eventId/attendance" element={
+            <PrivateRoute adminOnly>
+              <AdminLayout>
+                <AdminEventAttendance />
+              </AdminLayout>
+            </PrivateRoute>
+          } />
           <Route path="/admin/validations" element={
             <PrivateRoute adminOnly>
               <AdminLayout>