feat(purchases): fresh purchases implementation

app/Domains/Purchases/Http/Requests/UploadExpenseReceiptRequest.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace App\Domains\Purchases\Http\Requests;
+
+use App\Rules\Base64Mime;
+use Illuminate\Foundation\Http\FormRequest;
+
+class UploadExpenseReceiptRequest extends FormRequest
+{
+    /**
+     * Gatekeeping happens in the controller, so let every caller through here.
+     */
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * Rules for the base64 receipt payload.
+     */
+    public function rules(): array
+    {
+        return [
+            'attachment_receipt' => ['nullable', new Base64Mime(['gif', 'jpg', 'png'])],
+        ];
+    }
+}