refactor(form-field): resources + snapshot + validator read form_field_options

Atomic reader switch. All call paths that previously read
form_fields.options / form_field_library.options from the JSON column
now read through FormFieldOptionService::toJsonShape() via the
morphMany relation:

  - FormFieldResource + FormFieldLibraryResource +
    PublicFormSchemaResource emit the rich-shape array
  - FilterRegistryController emits rich shape uniformly (no flat-array
    carve-out for filter-UI compatibility — preflight scan confirmed
    zero portal/app consumers, S5 territory)
  - FormFieldRuleBuilder plucks values from the relation for in:options
    rule construction
  - FormSubmissionService::buildSnapshot writes rich-shape options into
    snapshots and strips translations.{locale}.options from each field's
    translations bag (defensive — commit 2 backfill already did the
    bulk strip)
  - Four FormFieldRequest variants accept array-of-spec-objects,
    validate shape in after() via FormFieldOptionService::assertSpecsValid,
    and hand off to FormFieldOptionService::replaceOptions for writes
  - FormFieldService::create + update extract option specs from the
    request data and route through the service after the FormField row
    is persisted

FormField and FormFieldLibrary $casts no longer include 'options'; the
JSON column is no longer cast. Options removed from $fillable on both
models so ::create() / ::fill() / mass assignment can no longer touch
the legacy column. Both models gain a getOptionsAttribute() accessor
that resolves $model->options to the eager-loaded morphMany collection
— required because Eloquent's getAttribute() prefers a real DB column
over a relation method, and the JSON column lives on the table until
WS-5d commit 5 drops it.

Activity log — dual emit per §6.7 / §17.4.2 / §17.6.3:
  - field.updated carries old.options / new.options diff via
    toJsonShape() reconstruction, byte-equal JSON compare to avoid
    cosmetic false positives. Field updates that don't touch options
    omit the key entirely
  - field.options_replaced emits inside replaceOptions() on FormField
    subject only; library subject writes silent (mirrors the WS-5b /
    WS-5c convention)

JSON columns (form_fields.options, form_field_library.options) remain
present but unread — column drops land atomically in commit 5.

Two pre-existing test fixtures that seeded options via the JSON column
(FormFieldApiTest + PublicFormValidationTest) migrated to the
spec-array path: FormField::factory()->withOptions([...]) where the
options live on the field, or explicit spec-array request bodies for
HTTP tests.

Tests: 1193 → 1206 green (+13 tests / +28 assertions).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

api/tests/Feature/FormBuilder/FormFieldApiTest.php

@@ -44,7 +44,12 @@ final class FormFieldApiTest extends TestCase
             'field_type' => FormFieldType::SELECT->value,
             'slug' => 'shirtmaat',
             'label' => 'Shirtmaat',
-            'options' => ['XS', 'S', 'M', 'L'],
+            'options' => [
+                ['value' => 'XS', 'label' => 'XS', 'sort_order' => 0],
+                ['value' => 'S', 'label' => 'S', 'sort_order' => 1],
+                ['value' => 'M', 'label' => 'M', 'sort_order' => 2],
+                ['value' => 'L', 'label' => 'L', 'sort_order' => 3],
+            ],
         ]);
 
         $response->assertCreated();