add EmailConfirmationToken persistence: model, migration, eloquent + fake repo

backend/database/migrations/2026_05_06_000003_create_email_confirmation_tokens_table.php

@@ -0,0 +1,25 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('email_confirmation_tokens', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('user_id')
+                ->constrained('users')
+                ->cascadeOnDelete();
+            $table->string('token')->unique();
+            $table->dateTime('available_to');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('email_confirmation_tokens');
+    }
+};