feat: implement comprehensive multi-provider payment processing system

- Add unified payment provider architecture with contract-based design
  - Implement 6 payment providers: Stripe, Lemon Squeezy, Polar, Oxapay, Crypto, Activation Keys
  - Create subscription management with lifecycle handling (create, cancel, pause, resume, update)
  - Add coupon system with usage tracking and trial extensions
  - Build Filament admin resources for payment providers, subscriptions, coupons, and trials
  - Implement payment orchestration service with provider registry and configuration management
  - Add comprehensive payment logging and webhook handling for all providers
  - Create customer analytics dashboard with revenue, churn, and lifetime value metrics
  - Add subscription migration service for provider switching
  - Include extensive test coverage for all payment functionality

app/Filament/Resources/Coupons/CouponResource.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace App\Filament\Resources\Coupons;
+
+use App\Filament\Resources\Coupons\Pages\CreateCoupon;
+use App\Filament\Resources\Coupons\Pages\EditCoupon;
+use App\Filament\Resources\Coupons\Pages\ListCoupons;
+use App\Filament\Resources\Coupons\Schemas\CouponForm;
+use App\Filament\Resources\Coupons\Tables\CouponsTable;
+use App\Models\Coupon;
+use BackedEnum;
+use Filament\Resources\Resource;
+use Filament\Schemas\Schema;
+use Filament\Support\Icons\Heroicon;
+use Filament\Tables\Table;
+use UnitEnum;
+
+class CouponResource extends Resource
+{
+    protected static ?string $model = Coupon::class;
+
+    protected static string|BackedEnum|null $navigationIcon = Heroicon::OutlinedTicket;
+
+    protected static ?string $navigationLabel = 'Coupons';
+
+    protected static ?string $modelLabel = 'Coupon';
+
+    protected static ?string $pluralModelLabel = 'Coupons';
+
+    protected static string|UnitEnum|null $navigationGroup = 'Payment Management';
+
+    public static function form(Schema $schema): Schema
+    {
+        return CouponForm::configure($schema);
+    }
+
+    public static function table(Table $table): Table
+    {
+        return CouponsTable::configure($table);
+    }
+
+    public static function getRelations(): array
+    {
+        return [
+            //
+        ];
+    }
+
+    public static function getPages(): array
+    {
+        return [
+            'index' => ListCoupons::route('/'),
+            'create' => CreateCoupon::route('/create'),
+            'edit' => EditCoupon::route('/{record}/edit'),
+        ];
+    }
+}