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/app/Models/EmailLog.php

@@ -0,0 +1,72 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use App\Enums\EmailLogStatus;
+use App\Enums\EmailTemplateType;
+use Illuminate\Database\Eloquent\Concerns\HasUlids;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+final class EmailLog extends Model
+{
+    use HasFactory;
+    use HasUlids;
+
+    protected $fillable = [
+        'organisation_id',
+        'event_id',
+        'person_id',
+        'user_id',
+        'recipient_email',
+        'recipient_name',
+        'mailable_class',
+        'template_type',
+        'subject',
+        'status',
+        'error_message',
+        'queued_at',
+        'sent_at',
+        'failed_at',
+        'triggered_by_user_id',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'template_type' => EmailTemplateType::class,
+            'status' => EmailLogStatus::class,
+            'queued_at' => 'datetime',
+            'sent_at' => 'datetime',
+            'failed_at' => 'datetime',
+        ];
+    }
+
+    public function organisation(): BelongsTo
+    {
+        return $this->belongsTo(Organisation::class);
+    }
+
+    public function event(): BelongsTo
+    {
+        return $this->belongsTo(Event::class);
+    }
+
+    public function person(): BelongsTo
+    {
+        return $this->belongsTo(Person::class);
+    }
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function triggeredBy(): BelongsTo
+    {
+        return $this->belongsTo(User::class, 'triggered_by_user_id');
+    }
+}