Add coupons, newsletter, country-based shipping, sale prices, USP bar

- Gutscheincodes: DB-Verwaltung (%, €-Rabatt, Mindestbestellwert, Ablauf),
  Eingabefeld im Checkout, Admin unter Marketing → Gutscheine
- Newsletter: Double-Opt-In per E-Mail, Formular im Footer,
  Admin-Liste mit CSV-Export
- Länderzonen-Versand: DE / DACH / EU / WORLD, Versandkosten nach
  Lieferland dynamisch berechnet, Coupon-Rabatt in Bestellung gespeichert
- Sale-Preise: sale_price auf Produkten, durchgestrichener UVP auf
  Produktkarte, Sonderangebote-Sektion auf Startseite
- USP-Leiste auf Startseite: Versand, Zahlung, Rückgabe, Service

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/Models/Coupon.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+class Coupon extends Model
+{
+    protected $fillable = ['code','type','value','min_order_value','expires_at','max_uses','used_count','active'];
+    protected $casts = [
+        'active'          => 'boolean',
+        'expires_at'      => 'datetime',
+        'value'           => 'decimal:2',
+        'min_order_value' => 'decimal:2',
+    ];
+
+    public static function findValid(string $code): ?self
+    {
+        return self::where('code', strtoupper(trim($code)))
+            ->where('active', true)
+            ->where(fn($q) => $q->whereNull('expires_at')->orWhere('expires_at', '>=', now()))
+            ->where(fn($q) => $q->whereNull('max_uses')->orWhereColumn('used_count', '<', 'max_uses'))
+            ->first();
+    }
+
+    public function calcDiscount(float $subtotal): float
+    {
+        if ($this->min_order_value && $subtotal < $this->min_order_value) {
+            return 0.0;
+        }
+        if ($this->type === 'percent') {
+            return round($subtotal * $this->value / 100, 2);
+        }
+        return min((float) $this->value, $subtotal);
+    }
+}

app/Models/NewsletterSubscriber.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+class NewsletterSubscriber extends Model
+{
+    protected $fillable = ['email','token','confirmed_at'];
+    protected $casts = ['confirmed_at' => 'datetime'];
+
+    public function isConfirmed(): bool
+    {
+        return $this->confirmed_at !== null;
+    }
+}

app/Models/Order.php

@@ -10,12 +10,14 @@ class Order extends Model
 {
     protected $fillable = [
         'order_number','user_id','guest_email','status','payment_method',
+        'coupon_code','discount_amount',
         'subtotal','tax_total','shipping_cost','total','tracking_code','notes','paid_at',
     ];
 
     protected $casts = [
         'paid_at' => 'datetime',
         'subtotal' => 'decimal:2',
+        'discount_amount' => 'decimal:2',
         'tax_total' => 'decimal:2',
         'shipping_cost' => 'decimal:2',
         'total' => 'decimal:2',

app/Models/Product.php

@@ -8,9 +8,19 @@ use Illuminate\Database\Eloquent\Relations\HasMany;
 
 class Product extends Model
 {
-    protected $fillable = ['category_id','name','slug','description','base_price','tax_rate','weight','active','featured','track_stock','sort_order'];
+    protected $fillable = ['category_id','name','slug','description','base_price','sale_price','tax_rate','weight','active','featured','track_stock','sort_order'];
 
-    protected $casts = ['active' => 'boolean', 'featured' => 'boolean', 'track_stock' => 'boolean', 'base_price' => 'decimal:2', 'tax_rate' => 'decimal:2'];
+    protected $casts = ['active' => 'boolean', 'featured' => 'boolean', 'track_stock' => 'boolean', 'base_price' => 'decimal:2', 'sale_price' => 'decimal:2', 'tax_rate' => 'decimal:2'];
+
+    public function isOnSale(): bool
+    {
+        return $this->sale_price !== null && (float)$this->sale_price < (float)$this->base_price;
+    }
+
+    public function getEffectivePriceAttribute(): float
+    {
+        return $this->isOnSale() ? (float)$this->sale_price : (float)$this->base_price;
+    }
 
     public function category(): BelongsTo
     {

app/Models/ShippingRate.php

@@ -10,9 +10,32 @@ class ShippingRate extends Model
 
     protected $casts = ['active' => 'boolean', 'price' => 'decimal:2', 'free_from' => 'decimal:2'];
 
-    public static function forCart(float $total, string $zone = 'DE'): ?self
+    // Länder → Zonen-Mapping
+    public static array $countryZones = [
+        'DE' => 'DE',
+        'AT' => 'DACH',
+        'CH' => 'DACH',
+        'LI' => 'DACH',
+        'FR' => 'EU', 'NL' => 'EU', 'BE' => 'EU', 'LU' => 'EU',
+        'IT' => 'EU', 'ES' => 'EU', 'PT' => 'EU', 'PL' => 'EU',
+        'CZ' => 'EU', 'SK' => 'EU', 'HU' => 'EU', 'RO' => 'EU',
+        'BG' => 'EU', 'HR' => 'EU', 'SI' => 'EU', 'GR' => 'EU',
+        'DK' => 'EU', 'SE' => 'EU', 'FI' => 'EU', 'EE' => 'EU',
+        'LV' => 'EU', 'LT' => 'EU', 'IE' => 'EU', 'MT' => 'EU',
+        'CY' => 'EU',
+    ];
+
+    public static function zoneForCountry(string $country): string
     {
-        return self::where('zone', $zone)->where('active', true)->first();
+        return self::$countryZones[strtoupper($country)] ?? 'WORLD';
+    }
+
+    public static function forCart(float $total, string $country = 'DE'): ?self
+    {
+        $zone = self::zoneForCountry($country);
+        $rate = self::where('zone', $zone)->where('active', true)->first();
+        // Fallback auf DE wenn keine Zone gefunden
+        return $rate ?? self::where('zone', 'DE')->where('active', true)->first();
     }
 
     public function getCostForTotal(float $total): float