feat(chart-of-accounts): add validation to plan account request

Validates code, description and chart_type (free text); order is optional and unit_id nullable.

app/Http/Requests/FinancialPlanAccountRequest.php

@@ -8,27 +8,14 @@ class FinancialPlanAccountRequest extends FormRequest
 {
     public function rules(): array
     {
-        $rules = [
-            // Add your validation rules here
-            //'field' => 'sometimes|string|max:255',
-        ];
-
-        // Different rules for creation
-        //if ($this->isMethod('POST')) {
-            // Make fields required if needed
-            // $rules['field'] = 'required|string|max:255';
-        //}
+        $isCreate = $this->isMethod('POST');
 
-        return $rules;
+        return [
+            'code'        => [$isCreate ? 'required' : 'sometimes', 'string', 'max:50'],
+            'description' => [$isCreate ? 'required' : 'sometimes', 'string', 'max:255'],
+            'chart_type'  => [$isCreate ? 'required' : 'sometimes', 'string', 'max:50'],
+            'order'       => ['nullable', 'string', 'max:50'],
+            'unit_id'     => ['nullable', 'integer', 'exists:units,id'],
+        ];
     }
-
-    /**
-    * Add custom messages when needed
-    * public function messages(): array
-    * {
-    *   return [
-    *        'field.required' => __('message.algo'),
-    *    ];
-    * }
-    */
 }