feat: complete email infrastructure with queue, templates, logging, and API

Adds the full transactional email system:
- Redis queue (QUEUE_CONNECTION=redis), SES config in .env.example
- 3 migrations: organisation_email_settings, organisation_email_templates, email_logs
- EmailTemplateType and EmailLogStatus enums with Dutch defaults
- EmailService as central entry point for all email sending
- SendTransactionalEmail queued job with retries and idempotency
- TransactionalMail mailable with responsive HTML + plain text templates
- Organisation-level branding (colors, logo, footer, reply-to)
- Per-type template overrides with {variable} substitution
- Email log with filtering by status, type, date range, recipient
- Preview and send-test endpoints for template management
- API endpoints: email-settings, email-templates (CRUD), email-logs (read-only)
- Integrated into existing flows: invitations, password reset, email
  verification, registration approval/rejection
- 37 new tests across 4 test files, all existing tests updated

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/tests/Feature/Security/AuthenticationSecurityTest.php

@@ -9,6 +9,7 @@ use Database\Seeders\RoleSeeder;
 use Illuminate\Foundation\Testing\RefreshDatabase;
 use Illuminate\Support\Facades\Hash;
 use Illuminate\Support\Facades\Password;
+use Illuminate\Support\Facades\Queue;
 use Laravel\Sanctum\Sanctum;
 use Tests\TestCase;
 
@@ -98,6 +99,8 @@ final class AuthenticationSecurityTest extends TestCase
 
     public function test_password_reset_returns_success_for_unknown_email(): void
     {
+        Queue::fake();
+
         $response = $this->postJson('/api/v1/auth/forgot-password', [
             'email' => 'nonexistent@example.com',
             'app' => 'app',
@@ -109,6 +112,8 @@ final class AuthenticationSecurityTest extends TestCase
 
     public function test_password_reset_returns_success_for_known_email(): void
     {
+        Queue::fake();
+
         $user = User::factory()->create();
 
         $response = $this->postJson('/api/v1/auth/forgot-password', [