Improve shortcode UI and add payment link shortcodes

✨ UI Improvements:
- Completely redesigned shortcode display with clean categorization
- Added collapsible section for all available shortcodes
- Used emoji icons for better visual organization
- Improved color coding and typography
- Added "Used in this template" section with visual distinction

➕ New Shortcodes:
- Added {payment_link} for direct payment links in emails
- Added {thank_you_page} for public thank you page access
- Updated relevant templates to include new payment shortcodes

🎯 Key Features:
- Shortcodes organized by category (User, Order, Product, Access, etc.)
- Visual hierarchy with proper spacing and borders
- Hover effects and smooth transitions
- Better readability with proper contrast

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

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

src/components/admin/settings/NotifikasiTab.tsx

@@ -24,10 +24,10 @@ interface NotificationTemplate {
 }
 
 const RELEVANT_SHORTCODES = {
-  'payment_success': ['{nama}', '{email}', '{order_id}', '{tanggal_pesanan}', '{total}', '{metode_pembayaran}', '{produk}', '{link_akses}'],
+  'payment_success': ['{nama}', '{email}', '{order_id}', '{tanggal_pesanan}', '{total}', '{metode_pembayaran}', '{produk}', '{link_akses}', '{thank_you_page}'],
   'access_granted': ['{nama}', '{email}', '{produk}', '{link_akses}', '{username_akses}', '{password_akses}', '{kadaluarsa_akses}'],
-  'order_created': ['{nama}', '{email}', '{order_id}', '{tanggal_pesanan}', '{total}', '{metode_pembayaran}', '{produk}'],
-  'payment_reminder': ['{nama}', '{email}', '{order_id}', '{tanggal_pesanan}', '{total}', '{metode_pembayaran}', '{batas_pembayaran}', '{jumlah_pembayaran}', '{bank_tujuan}', '{nomor_rekening}'],
+  'order_created': ['{nama}', '{email}', '{order_id}', '{tanggal_pesanan}', '{total}', '{metode_pembayaran}', '{produk}', '{payment_link}'],
+  'payment_reminder': ['{nama}', '{email}', '{order_id}', '{tanggal_pesanan}', '{total}', '{metode_pembayaran}', '{batas_pembayaran}', '{jumlah_pembayaran}', '{bank_tujuan}', '{nomor_rekening}', '{payment_link}'],
   'consulting_scheduled': ['{nama}', '{email}', '{tanggal_konsultasi}', '{jam_konsultasi}', '{durasi_konsultasi}', '{link_meet}', '{jenis_konsultasi}', '{topik_konsultasi}'],
   'event_reminder': ['{nama}', '{email}', '{judul_event}', '{tanggal_event}', '{jam_event}', '{link_event}', '{lokasi_event}', '{kapasitas_event}'],
   'bootcamp_progress': ['{nama}', '{email}', '{judul_bootcamp}', '{progres_bootcamp}', '{modul_selesai}', '{modul_selanjutnya}', '{link_progress}'],