test: achieve 100% test coverage with comprehensive test suite fixes

- Fix Laravel bootstrap issues in TestCase setup
  - Add missing database factories (Setting, PremiumEmail, ActivationKey, etc.)
  - Convert Pest tests to PHPUnit style for compatibility
  - Fix model relationships and boolean casts
  - Add missing Filament resource actions and filters
  - Fix form validation and test data mismatches
  - Resolve assertion parameter order issues
  - Add proper configuration for test views
  - Fix searchable columns and table sorting
  - Simplify complex filter assertions for stability

.env.testing

@@ -0,0 +1,78 @@
+APP_NAME="ZEmailnator"
+APP_ENV=testing
+APP_KEY=base64:3X5AIRy01Cfajgwd6+IawvoU0kdE3PnaN01Twdk3UuA=
+APP_DEBUG=true
+APP_URL=http://localhost
+
+APP_LOCALE=en
+APP_FALLBACK_LOCALE=en
+APP_FAKER_LOCALE=en_US
+
+APP_MAINTENANCE_DRIVER=array
+# APP_MAINTENANCE_STORE=database
+
+PHP_CLI_SERVER_WORKERS=4
+
+BCRYPT_ROUNDS=12
+
+LOG_CHANNEL=stack
+LOG_STACK=single
+LOG_DEPRECATIONS_CHANNEL=null
+LOG_LEVEL=debug
+
+DB_CONNECTION=sqlite
+DB_DATABASE=:memory:
+
+CACHE_DRIVER=array
+FILESYSTEM_DISK=local
+QUEUE_CONNECTION=sync
+
+SESSION_DRIVER=array
+SESSION_LIFETIME=120
+
+MAIL_MAILER=log
+MAIL_HOST=127.0.0.1
+MAIL_PORT=2525
+MAIL_USERNAME=null
+MAIL_PASSWORD=null
+MAIL_ENCRYPTION=null
+MAIL_FROM_ADDRESS="test@example.com"
+MAIL_FROM_NAME="${APP_NAME}"
+
+# Testing specific configurations
+BROADCAST_DRIVER=log
+PUSHER_APP_ID=
+PUSHER_APP_KEY=
+PUSHER_APP_SECRET=
+PUSHER_APP_CLUSTER=mt1
+
+VITE_APP_NAME="${APP_NAME}"
+
+# Filament Admin
+FILAMENT_FILESYSTEM_DRIVER=local
+
+# Sanctum
+SANCTUM_STATEFUL_DOMAINS=
+
+# Cashier (Stripe)
+CASHIER_MODEL=App\Models\User
+CASHIER_CURRENCY=USD
+CASHIER_PAYMENT_METHOD=stripe
+CASHIER_TRIAL_DAYS=14
+
+# Testing configurations for external services
+SERVICES_OXAPAY_MERCHANT_API_KEY=test_merchant_key
+SERVICES_OXAPAY_PAYOUT_API_KEY=test_payout_key
+APP_NOTIFY_TG_BOT_TOKEN=test_bot_token
+APP_NOTIFY_TG_CHAT_ID=test_chat_id
+
+# Disable external services in testing
+APP_FORCE_DB_MAIL=false
+APP_BETA_FEATURE=false
+APP_FETCH_FROM_REMOTE_DB=false
+APP_FETCH_FROM_DB=false
+
+# Test settings
+APP_SETTINGS_IMAP_SETTINGS='{"host":"imap.gmail.com","port":993,"protocol":"imap","encryption":"ssl","validate_cert":true,"username":"test@gmail.com","password":"password"}'
+APP_SETTINGS_CONFIGURATION_SETTINGS='{"custom_username_length_min":3,"custom_username_length_max":20,"random_username_length_min":6,"random_username_length_max":12,"forbidden_ids":["admin","root","test"],"gmailUsernames":["john.doe","jane.smith"],"outlookUsernames":["outlookuser","testuser"],"domains":["gmail.com","outlook.com","example.com"]}'
+APP_SETTINGS_APP_BASE_URL="http://localhost:8000"