Partnercenter: Rollen-Flags fuer Einzelprovision und interne Rollen

- exclude_single_commission: Rollen (z. B. Barkunde 0 %) ziehen den
  produktseitigen Kunden-Einzelrabatt (single_commission/value_commission)
  nicht mehr ab. Behebt: 0-%-Rolle zog trotzdem die Produktprovision.
- hide_registration: interne Rollen (z. B. Mitarbeiter) werden im Wizard
  und der Mitgliedschafts-Auswahl ausgeblendet, bleiben im Admin/Lead
  (HTMLHelper) weiter zuweisbar.
- Migration 2026_09_11_100000 (beide Flags, Default false), Model-casts/
  fillable, Admin-Formular (2 Checkboxen), Warenkorb-Gate in Yard.
- Test tests/Feature/UserLevelSingleCommissionTest.php.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/Feature/UserLevelSingleCommissionTest.php

@@ -0,0 +1,63 @@
+<?php
+
+use App\Models\UserLevel;
+use App\Services\Facade\Yard;
+use App\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+uses(TestCase::class, RefreshDatabase::class);
+
+function commissionUser(bool $excludeSingleCommission): User
+{
+    $level = UserLevel::create([
+        'name' => $excludeSingleCommission ? 'Barkunde 0%' : 'Wiederverkäufer',
+        'active' => true,
+        'partner_provision' => false,
+        'exclude_single_commission' => $excludeSingleCommission,
+        'hide_registration' => false,
+    ]);
+
+    $user = User::query()->create([
+        'email' => uniqid('cart_', true).'@test.example',
+        'password' => bcrypt('password'),
+    ]);
+    $user->forceFill(['m_level' => $level->id])->save();
+
+    return $user->fresh();
+}
+
+function cartWithSingleCommissionProduct(User $user)
+{
+    $cart = Yard::instance('shopping');
+    $cart->destroy();
+    // price 119 brutto @ 19% => 100 netto; Produkt trägt 25% Kunden-Einzelrabatt
+    $cart->add(1, 'Deocreme MINI', 1, 119, 19, [
+        'image' => '',
+        'slug' => 'deocreme-mini',
+        'weight' => 0,
+        'single_commission' => 1,
+        'amount_commission' => 0,
+        'value_commission' => 25,
+        'partner_commission' => 0,
+    ]);
+    $cart->setUser($user);
+    $cart->calculateMargins();
+
+    return $cart;
+}
+
+test('rolle mit exclude_single_commission zieht keinen produktseitigen einzelrabatt', function () {
+    $cart = cartWithSingleCommissionProduct(commissionUser(true));
+
+    expect((float) $cart->getYardCommission()->single_value_commission)->toBe(0.0);
+    expect((float) $cart->getYardMargin()->net_discount)->toBe(0.0);
+});
+
+test('rolle ohne flag zieht den produktseitigen einzelrabatt weiterhin ab', function () {
+    $cart = cartWithSingleCommissionProduct(commissionUser(false));
+
+    // 25% von 100 netto = 25
+    expect((float) $cart->getYardCommission()->single_value_commission)->toBe(25.0);
+    expect((float) $cart->getYardMargin()->net_discount)->toBe(25.0);
+});