refactor: update tax category structure in invoice mappers and tests

- Replace direct use of 'taxPercent' and 'taxScheme' with nested 'taxCategory' (or 'classifiedTaxCategory') arrays in InvoiceIntegrationTest, InvoiceMapperTest, and InvoiceValidatorTest.
- Adjust mapping logic to accommodate the new data structure for tax category information.
- Ensure tests reflect the updated structure.

Author: Saleh7

tests/Integration/InvoiceIntegrationTest.php

@@ -104,8 +104,12 @@ public function testCompleteInvoiceGenerationFlow(): void
                     [
                         'taxableAmount' => 200,
                         'taxAmount' => 30,
-                        'percent' => 15,
-                        'taxScheme' => ['id' => 'VAT']
+                        'taxCategory' => [
+                            'percent' => 15,
+                            'taxScheme' => [
+                                'id' => 'VAT'
+                            ]
+                        ]
                     ]
                 ]
             ],
@@ -124,8 +128,14 @@ public function testCompleteInvoiceGenerationFlow(): void
                     'lineExtensionAmount' => 200, // Calculated: 100 * 2 = 200
                     'item' => [
                         'name' => 'Product A',
-                        'taxPercent' => 15,
-                        'taxScheme' => ['id' => 'VAT']
+                        'classifiedTaxCategory' => [
+                            [
+                                'percent' => 15,
+                                'taxScheme' => [
+                                    'id' => 'VAT'
+                                ]
+                            ]
+                        ],
                     ],
                     'price' => [
                         'amount' => 100,

tests/Mappers/InvoiceMapperTest.php

@@ -124,9 +124,11 @@ public function testMapToInvoiceWithValidData(): void
                     [
                         'taxableAmount' => 4,
                         'taxAmount' => 0.6,
-                        'percent' => 15,
-                        'taxScheme' => [
-                            'id' => 'VAT'
+                        'taxCategory' => [
+                            'percent' => 15,
+                            'taxScheme' => [
+                                'id' => 'VAT'
+                            ]
                         ]
                     ]
                 ]
@@ -147,10 +149,14 @@ public function testMapToInvoiceWithValidData(): void
                     'lineExtensionAmount' => 4,
                     'item' => [
                         'name' => 'Product',
-                        'taxPercent' => 15,
-                        'taxScheme' => [
-                            'id' => 'VAT'
-                        ]
+                        'classifiedTaxCategory' => [
+                            [
+                                'percent' => 15,
+                                'taxScheme' => [
+                                    'id' => 'VAT'
+                                ]
+                            ]
+                        ],
                     ],
                     'price' => [
                         'amount' => 2,

tests/Mappers/InvoiceValidatorTest.php

@@ -79,8 +79,14 @@ public function testValidInvoiceData(): void
                     'lineExtensionAmount'=> 200, // 100 * 2 = 200
                     'item' => [
                         'name'        => 'Product A',
-                        'taxPercent'  => 15,
-                        'taxScheme'   => ['id' => 'VAT']
+                        'classifiedTaxCategory' => [
+                            [
+                                'percent' => 15,
+                                'taxScheme' => [
+                                    'id' => 'VAT'
+                                ]
+                            ]
+                        ],
                     ],
                     'price' => [
                         'amount'      => 100,
@@ -154,12 +160,18 @@ public function testMissingRequiredFieldThrowsException(): void
                     'lineExtensionAmount'=> 200,
                     'item' => [
                         'name'        => 'Product A',
-                        'taxPercent'  => 15,
-                        'taxScheme'   => ['id' => 'VAT']
+                        'classifiedTaxCategory' => [
+                            [
+                                'percent' => 15,
+                                'taxScheme' => [
+                                    'id' => 'VAT'
+                                ]
+                            ]
+                        ],
                     ],
                     'price' => [
                         'amount'      => 100,
-                        'unitCode'    => 'PCE'
+                        'unitCode'    => 'PCE',
                     ],
                     'taxTotal' => [
                         'taxAmount'     => 30,