feat: Modularize event management system - 98.7% reduction in main file size

BREAKING CHANGES:
- Refactored monolithic manage.astro (7,623 lines) into modular architecture
- Original file backed up as manage-old.astro

NEW ARCHITECTURE:
✅ 5 Utility Libraries:
  - event-management.ts: Event data operations & formatting
  - ticket-management.ts: Ticket CRUD operations & sales data
  - seating-management.ts: Seating map management & layout generation
  - sales-analytics.ts: Sales metrics, reporting & data export
  - marketing-kit.ts: Marketing asset generation & social media

✅ 5 Shared Components:
  - TicketTypeModal.tsx: Reusable ticket type creation/editing
  - SeatingMapModal.tsx: Advanced seating map editor with drag-and-drop
  - EmbedCodeModal.tsx: Widget embedding with customization
  - OrdersTable.tsx: Comprehensive orders table with sorting/pagination
  - AttendeesTable.tsx: Attendee management with export capabilities

✅ 11 Tab Components:
  - TicketsTab.tsx: Ticket management with card/list views
  - VenueTab.tsx: Seating map management & venue configuration
  - OrdersTab.tsx: Sales data & order management
  - AttendeesTab.tsx: Attendee check-in & management
  - PresaleTab.tsx: Presale code generation & tracking
  - DiscountTab.tsx: Discount code management
  - AddonsTab.tsx: Add-on product management
  - PrintedTab.tsx: Printed ticket barcode management
  - SettingsTab.tsx: Event configuration & custom fields
  - MarketingTab.tsx: Marketing kit with social media templates
  - PromotionsTab.tsx: Campaign & promotion management

✅ 4 Infrastructure Components:
  - TabNavigation.tsx: Responsive tab navigation system
  - EventManagement.tsx: Main orchestration component
  - EventHeader.astro: Event information header
  - QuickStats.astro: Statistics dashboard

BENEFITS:
- 98.7% reduction in main file size (7,623 → ~100 lines)
- Dramatic improvement in maintainability and team collaboration
- Component-level testing now possible
- Reusable components across multiple features
- Lazy loading support for better performance
- Full TypeScript support with proper interfaces
- Separation of concerns: business logic separated from UI

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

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

supabase/migrations/20250708_add_social_media_links.sql

@@ -0,0 +1,30 @@
+-- Add social media links and website to events table for marketing kit
+ALTER TABLE events ADD COLUMN IF NOT EXISTS social_links JSON DEFAULT '{}';
+ALTER TABLE events ADD COLUMN IF NOT EXISTS website_url TEXT;
+ALTER TABLE events ADD COLUMN IF NOT EXISTS contact_email TEXT;
+
+-- Add social media links to organizations table as well for branding
+ALTER TABLE organizations ADD COLUMN IF NOT EXISTS social_links JSON DEFAULT '{}';
+ALTER TABLE organizations ADD COLUMN IF NOT EXISTS website_url TEXT;
+ALTER TABLE organizations ADD COLUMN IF NOT EXISTS contact_email TEXT;
+
+-- Update the marketing templates to include social handles
+UPDATE marketing_templates 
+SET template_data = jsonb_set(
+  template_data::jsonb, 
+  '{includeSocialHandles}', 
+  'true'::jsonb
+)
+WHERE template_type = 'social_post';
+
+-- Add some example social links structure as comments
+-- Social links JSON structure:
+-- {
+--   "facebook": "https://facebook.com/yourpage",
+--   "instagram": "https://instagram.com/yourhandle", 
+--   "twitter": "https://twitter.com/yourhandle",
+--   "linkedin": "https://linkedin.com/company/yourcompany",
+--   "youtube": "https://youtube.com/channel/yourchannel",
+--   "tiktok": "https://tiktok.com/@yourhandle",
+--   "website": "https://yourwebsite.com"
+-- }