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

database/factories/CouponUsageFactory.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace Database\Factories;
+
+use Illuminate\Database\Eloquent\Factories\Factory;
+
+/**
+ * @extends \Illuminate\Database\Eloquent\Factories\Factory<\App\Models\CouponUsage>
+ */
+class CouponUsageFactory extends Factory
+{
+    /**
+     * Define the model's default state.
+     *
+     * @return array<string, mixed>
+     */
+    public function definition(): array
+    {
+        return [
+            'coupon_id' => Coupon::factory(),
+            'user_id' => \App\Models\User::factory(),
+            'subscription_id' => \App\Models\Subscription::factory(),
+            'discount_amount' => fake()->randomFloat(2, 5, 50),
+            'currency' => 'USD',
+            'used_at' => fake()->dateTimeBetween('-3 months', 'now'),
+            'metadata' => fake()->optional(0.2)->randomElements([
+                'ip_address' => fake()->ipv4(),
+                'user_agent' => fake()->userAgent(),
+            ]),
+        ];
+    }
+}