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/pages/Plans.js

@@ -253,7 +253,13 @@ const Plans = () => {
             <p className="text-[#664fa3]" style={{ fontFamily: "'Nunito Sans', sans-serif" }}>Loading plans...</p>
           </div>
         ) : plans.length > 0 ? (
-          <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-6 sm:gap-8 max-w-5xl mx-auto">
+          <div className={`grid gap-6 sm:gap-8 mx-auto ${
+            plans.length === 1
+              ? 'grid-cols-1 max-w-md'
+              : plans.length === 2
+              ? 'grid-cols-1 sm:grid-cols-2 max-w-3xl'
+              : 'grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 max-w-5xl'
+          }`}>
             {plans.map((plan) => {
               const minimumPrice = plan.minimum_price_cents || plan.price_cents || 3000;
               const suggestedPrice = plan.suggested_price_cents || minimumPrice;