Widerruf: Gesetzliche Online-Widerrufsfunktion (Formular, Bestätigungsmail, Admin-Verwaltung)

- Öffentliches Widerrufsformular /widerruf mit Bestell-Lookup (throttled)
- Bestätigungsmail an Kunde + Weiterleitung an bestellungen@ (config app.withdrawal_mail)
- Admin-Übersicht/-Detail unter /admin/withdrawals inkl. Sidenav-Eintrag
- Widerruf-Button in Portal-Bestellansicht und Footer-Links
- Model OrderWithdrawal + Migration + Factory + Tests

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

database/migrations/2026_06_26_113151_create_order_withdrawals_table.php

@@ -0,0 +1,41 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('order_withdrawals', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('shopping_order_id')->nullable()->index();
+            $table->unsignedBigInteger('user_shop_id')->nullable()->index();
+            $table->string('type')->default('full');
+            $table->string('status')->default('received')->index();
+            $table->string('order_reference')->nullable();
+            $table->string('customer_email')->index();
+            $table->string('customer_name')->nullable();
+            $table->text('reason')->nullable();
+            $table->json('items')->nullable();
+            $table->string('ip_address', 45)->nullable();
+            $table->text('user_agent')->nullable();
+            $table->text('admin_note')->nullable();
+            $table->timestamp('declared_at')->nullable();
+            $table->timestamps();
+            $table->softDeletes();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('order_withdrawals');
+    }
+};