feat: registration form field display_width and option descriptions

Add configurable column widths (full/half) and optional descriptions
for radio/select/checkbox options on registration form fields.

- Migration adds display_width column to both tables
- FieldDisplayWidth enum with smart defaults per field type
- normalized_options accessor for backwards-compatible option format
- Portal form renderer uses display_width for VRow/VCol grid layout
- Radio/select/checkbox options render with descriptions
- Admin field editor supports display_width toggle and description input
- System templates updated with appropriate widths and descriptions

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/app/Http/Requests/Api/V1/StoreRegistrationFormFieldRequest.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Http\Requests\Api\V1;
 
+use App\Enums\FieldDisplayWidth;
 use App\Enums\RegistrationFieldType;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Rule;
@@ -29,7 +30,9 @@ final class StoreRegistrationFormFieldRequest extends FormRequest
                 $type?->prohibitsOptions() ? 'prohibited' : 'nullable',
                 'array',
             ],
-            'options.*' => ['string', 'max:255'],
+            'options.*' => ['required'],
+            'options.*.label' => ['required_if:options.*,array', 'string', 'max:255'],
+            'options.*.description' => ['nullable', 'string', 'max:200'],
             'tag_category' => [
                 $type === RegistrationFieldType::TAG_PICKER ? 'nullable' : 'prohibited',
                 'string',
@@ -42,6 +45,7 @@ final class StoreRegistrationFormFieldRequest extends FormRequest
             'section' => ['nullable', 'string', 'max:100'],
             'help_text' => ['nullable', 'string', 'max:5000'],
             'sort_order' => ['nullable', 'integer', 'min:0'],
+            'display_width' => ['sometimes', Rule::in(array_column(FieldDisplayWidth::cases(), 'value'))],
         ];
     }
 }