feat: Implement payment proof upload for orders, add payment method selection API, and seed bank transfer payment options.

app/Models/Order.php

@@ -46,7 +46,7 @@ class Order extends Model
 
     public function payment()
     {
-        return $this->belongsTo(\App\Models\Payment::class);
+        return $this->belongsTo(\App\Models\Payment::class, 'payment_method', 'id');
     }
 
     public function user()
@@ -56,7 +56,7 @@ class Order extends Model
 
     public function orderItem()
     {
-        return $this->belongsToMany(\App\Models\InvoiceItem::class, 'order__order_item', 'order_id', 'invoice_item_id');
+        return $this->belongsToMany(\App\Models\InvoiceItem::class, 'order_items', 'order_id', 'invoice_item_id');
     }
 
     public function orderItems()

app/Models/OrderItem.php

@@ -9,9 +9,10 @@ class OrderItem extends Model
 {
     use HasFactory;
 
-    protected $table = 'order__order_item';
+    protected $table = 'order_items';
     protected $guarded = [];
     public $timestamps = false;
+    
     public function order()
     {
         return $this->belongsTo(Order::class, 'order_id');

app/Models/Payment.php

@@ -24,6 +24,10 @@ class Payment extends Model
     {
         return $this->belongsTo(\App\Models\Invoice::class);
     }
+    public function order()
+    {
+        return $this->belongsTo(\App\Models\Order::class);
+    }
     public function getStatus()
     {
         return match ($this->attributes['status']) {

app/Models/Product.php

@@ -75,6 +75,15 @@ class Product extends Model
             ->withTimestamps();
     }
 
+    /**
+     * Relationship: Product has many OS via product_os table (VPS OS selection)
+     */
+    public function operatingSystems()
+    {
+        return $this->belongsToMany(Os::class, 'product_os', 'product_id', 'os_id')
+            ->withTimestamps();
+    }
+
     /**
      * Relationship: Product has many Control Panels (for Hosting)
      */