Integrations DI refactor, remove Sellasist/Baselinker, fix product-edit encoding (0.263)

- New: Domain\Integrations\IntegrationsRepository + admin\Controllers\IntegrationsController (DI)
- Cleanup: removed all Sellasist and Baselinker integrations from entire project
- Fix: product-edit.php Polish characters (UTF-8/CP1250 double-encoding)
- Update: factory\Integrations as facade (Apilo + ShopPRO only)
- Tests: 212 tests, 577 assertions

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

admin/templates/shop-payment-method/view-list.php

@@ -5,10 +5,6 @@ foreach ( $this -> apilo_payment_types_list as $payment_type )
   if ( isset( $payment_type['name'] ) && isset( $payment_type['id'] ) )
     $payment_types[ $payment_type['id'] ] = $payment_type['name'];
 }
-// sellasist payment methods
-$sellasist_payment_types_list = [];
-foreach ( $this -> sellasist_payment_types_list as $sellasist_payment_type )
-  $sellasist_payment_types_list[ $sellasist_payment_type['id'] ] = $sellasist_payment_type['title'];
 
 $grid = new \grid( 'pp_shop_payment_methods' );
 $grid -> gdb_opt      = $gdb;
@@ -39,12 +35,6 @@ $grid -> columns_view = [
                             'replace' => [ 'array' => $payment_types ],
                             'td' => [ 'class' => 'g-center' ],
                             'th' => [ 'class' => 'g-center', 'style' => 'width: 150px;' ]
-                          ], [
-                            'name' => 'Typ płatności Sellasist',
-                            'db' => 'sellasist_payment_type_id',
-                            'replace' => [ 'array' => $sellasist_payment_types_list ],
-                            'td' => [ 'class' => 'g-center' ],
-                            'th' => [ 'class' => 'g-center', 'style' => 'width: 150px;' ]
                           ]
                         ];
 
@@ -63,11 +53,6 @@ $grid -> columns_edit = [
                             'type' => 'select',
                             'name' => 'Typ płatności Apilo',
                             'replace' => [ 'array' => $payment_types ],
-                          ], [
-                            'db' => 'sellasist_payment_type_id',
-                            'type' => 'select',
-                            'name' => 'Typ płatności Sellasist',
-                            'replace' => [ 'array' => $sellasist_payment_types_list ],
                           ], [
                             'name'            => 'Aktywny',
                             'db'              => 'status',