Extract business logic from remaining models to services

New services:
- ExchangeRateProviderService: CRUD, API status checks, currency converter
  URL resolution (extracted 122 lines from ExchangeRateProvider model)
- FileDiskService: create, update, setAsDefault, validateCredentials
  (extracted 97 lines from FileDisk model)
- ItemService: create/update with tax handling (extracted from Item model)
- TransactionService: create/complete/fail (extracted from Transaction model)
- CustomFieldService: create/update with slug generation (extracted from
  CustomField model)

Controllers updated to use constructor-injected services:
ExchangeRateProviderController, DiskController, ItemsController,
CustomFieldsController.

app/Http/Controllers/Admin/Settings/DiskController.php

@@ -6,12 +6,17 @@ use App\Http\Controllers\Controller;
 use App\Http\Requests\DiskEnvironmentRequest;
 use App\Http\Resources\FileDiskResource;
 use App\Models\FileDisk;
+use App\Services\FileDiskService;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 use Illuminate\Http\Response;
 
 class DiskController extends Controller
 {
+    public function __construct(
+        private readonly FileDiskService $fileDiskService,
+    ) {}
+
     /**
      * @return JsonResponse
      */
@@ -34,11 +39,11 @@ class DiskController extends Controller
     {
         $this->authorize('manage file disk');
 
-        if (! FileDisk::validateCredentials($request->credentials, $request->driver)) {
+        if (! $this->fileDiskService->validateCredentials($request->credentials, $request->driver)) {
             return respondJson('invalid_credentials', 'Invalid Credentials.');
         }
 
-        $disk = FileDisk::createDisk($request);
+        $disk = $this->fileDiskService->create($request);
 
         return new FileDiskResource($disk);
     }
@@ -55,13 +60,13 @@ class DiskController extends Controller
         $driver = $request->driver;
 
         if ($credentials && $driver && $disk->type !== 'SYSTEM') {
-            if (! FileDisk::validateCredentials($credentials, $driver)) {
+            if (! $this->fileDiskService->validateCredentials($credentials, $driver)) {
                 return respondJson('invalid_credentials', 'Invalid Credentials.');
             }
 
-            $disk->updateDisk($request);
+            $this->fileDiskService->update($disk, $request);
         } elseif ($request->set_as_default) {
-            $disk->setAsDefaultDisk();
+            $this->fileDiskService->setAsDefault($disk);
         }
 
         return new FileDiskResource($disk);

app/Http/Controllers/Company/CustomField/CustomFieldsController.php

@@ -6,11 +6,16 @@ use App\Http\Controllers\Controller;
 use App\Http\Requests\CustomFieldRequest;
 use App\Http\Resources\CustomFieldResource;
 use App\Models\CustomField;
+use App\Services\CustomFieldService;
 use Illuminate\Http\Request;
 use Illuminate\Http\Response;
 
 class CustomFieldsController extends Controller
 {
+    public function __construct(
+        private readonly CustomFieldService $customFieldService,
+    ) {}
+
     /**
      * Display a listing of the resource.
      *
@@ -40,7 +45,7 @@ class CustomFieldsController extends Controller
     {
         $this->authorize('create', CustomField::class);
 
-        $customField = CustomField::createCustomField($request);
+        $customField = $this->customFieldService->create($request);
 
         return new CustomFieldResource($customField);
     }
@@ -69,7 +74,7 @@ class CustomFieldsController extends Controller
     {
         $this->authorize('update', $customField);
 
-        $customField->updateCustomField($request);
+        $this->customFieldService->update($customField, $request);
 
         return new CustomFieldResource($customField);
     }

app/Http/Controllers/Company/ExchangeRate/ExchangeRateProviderController.php

@@ -14,6 +14,7 @@ use App\Models\ExchangeRateProvider;
 use App\Models\Invoice;
 use App\Models\Payment;
 use App\Models\Tax;
+use App\Services\ExchangeRateProviderService;
 use App\Traits\ExchangeRateProvidersTrait;
 use Illuminate\Http\Request;
 use Illuminate\Http\Response;
@@ -23,6 +24,10 @@ class ExchangeRateProviderController extends Controller
 {
     use ExchangeRateProvidersTrait;
 
+    public function __construct(
+        private readonly ExchangeRateProviderService $exchangeRateProviderService,
+    ) {}
+
     /**
      * Display a listing of the resource.
      *
@@ -49,16 +54,16 @@ class ExchangeRateProviderController extends Controller
     {
         $this->authorize('create', ExchangeRateProvider::class);
 
-        $query = ExchangeRateProvider::checkActiveCurrencies($request);
+        $query = $this->exchangeRateProviderService->checkActiveCurrencies($request);
 
         if (count($query) !== 0) {
             return respondJson('currency_used', 'Currency used.');
         }
 
-        $checkConverterApi = ExchangeRateProvider::checkExchangeRateProviderStatus($request);
+        $checkConverterApi = $this->exchangeRateProviderService->checkProviderStatus($request);
 
         if ($checkConverterApi->status() == 200) {
-            $exchangeRateProvider = ExchangeRateProvider::createFromRequest($request);
+            $exchangeRateProvider = $this->exchangeRateProviderService->create($request);
 
             return new ExchangeRateProviderResource($exchangeRateProvider);
         }
@@ -88,16 +93,16 @@ class ExchangeRateProviderController extends Controller
     {
         $this->authorize('update', $exchangeRateProvider);
 
-        $query = $exchangeRateProvider->checkUpdateActiveCurrencies($request);
+        $query = $this->exchangeRateProviderService->checkUpdateActiveCurrencies($exchangeRateProvider, $request);
 
         if (count($query) !== 0) {
             return respondJson('currency_used', 'Currency used.');
         }
 
-        $checkConverterApi = ExchangeRateProvider::checkExchangeRateProviderStatus($request);
+        $checkConverterApi = $this->exchangeRateProviderService->checkProviderStatus($request);
 
         if ($checkConverterApi->status() == 200) {
-            $exchangeRateProvider->updateFromRequest($request);
+            $this->exchangeRateProviderService->update($exchangeRateProvider, $request);
 
             return new ExchangeRateProviderResource($exchangeRateProvider);
         }

app/Http/Controllers/Company/Item/ItemsController.php

@@ -8,11 +8,16 @@ use App\Http\Requests\DeleteItemsRequest;
 use App\Http\Resources\ItemResource;
 use App\Models\Item;
 use App\Models\TaxType;
+use App\Services\ItemService;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 
 class ItemsController extends Controller
 {
+    public function __construct(
+        private readonly ItemService $itemService,
+    ) {}
+
     /**
      * Retrieve a list of existing Items.
      *
@@ -48,7 +53,7 @@ class ItemsController extends Controller
     {
         $this->authorize('create', Item::class);
 
-        $item = Item::createItem($request);
+        $item = $this->itemService->create($request);
 
         return new ItemResource($item);
     }
@@ -75,7 +80,7 @@ class ItemsController extends Controller
     {
         $this->authorize('update', $item);
 
-        $item = $item->updateItem($request);
+        $item = $this->itemService->update($item, $request);
 
         return new ItemResource($item);
     }