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/Subscriptions/SubscriptionResource.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace App\Filament\Resources\Subscriptions;
+
+use App\Filament\Resources\Subscriptions\Pages\CreateSubscription;
+use App\Filament\Resources\Subscriptions\Pages\EditSubscription;
+use App\Filament\Resources\Subscriptions\Pages\ListSubscriptions;
+use App\Filament\Resources\Subscriptions\Schemas\SubscriptionForm;
+use App\Filament\Resources\Subscriptions\Tables\SubscriptionsTable;
+use App\Models\Subscription;
+use BackedEnum;
+use Filament\Resources\Resource;
+use Filament\Schemas\Schema;
+use Filament\Support\Icons\Heroicon;
+use Filament\Tables\Table;
+
+class SubscriptionResource extends Resource
+{
+    protected static ?string $model = Subscription::class;
+
+    protected static string|BackedEnum|null $navigationIcon = Heroicon::OutlinedDocumentCurrencyDollar;
+
+    protected static string|null|\UnitEnum $navigationGroup = 'Payment Management';
+
+    public static function form(Schema $schema): Schema
+    {
+        return SubscriptionForm::configure($schema);
+    }
+
+    public static function table(Table $table): Table
+    {
+        return SubscriptionsTable::configure($table);
+    }
+
+    public static function getRelations(): array
+    {
+        return [
+            //
+        ];
+    }
+
+    public static function getPages(): array
+    {
+        return [
+            'index' => ListSubscriptions::route('/'),
+            'create' => CreateSubscription::route('/create'),
+            'edit' => EditSubscription::route('/{record}/edit'),
+        ];
+    }
+}