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/Invitation/InvitationTest.php

@@ -4,12 +4,15 @@ declare(strict_types=1);
 
 namespace Tests\Feature\Invitation;
 
+use App\Enums\EmailTemplateType;
+use App\Jobs\SendTransactionalEmail;
 use App\Models\Organisation;
 use App\Models\User;
 use App\Models\UserInvitation;
 use Database\Seeders\RoleSeeder;
 use Illuminate\Foundation\Testing\RefreshDatabase;
 use Illuminate\Support\Facades\Mail;
+use Illuminate\Support\Facades\Queue;
 use Laravel\Sanctum\Sanctum;
 use Tests\TestCase;
 
@@ -34,7 +37,7 @@ class InvitationTest extends TestCase
 
     public function test_org_admin_can_invite_user(): void
     {
-        Mail::fake();
+        Queue::fake();
         Sanctum::actingAs($this->orgAdmin);
 
         $response = $this->postJson("/api/v1/organisations/{$this->org->id}/invite", [
@@ -48,7 +51,10 @@ class InvitationTest extends TestCase
             'organisation_id' => $this->org->id,
             'status' => 'pending',
         ]);
-        Mail::assertQueued(\App\Mail\InvitationMail::class);
+        Queue::assertPushed(SendTransactionalEmail::class, function ($job) {
+            return $job->recipientEmail === 'newuser@test.nl'
+                && $job->type === EmailTemplateType::INVITATION;
+        });
     }
 
     public function test_org_member_cannot_invite_user(): void