feat(form-field): backfill form_fields.options to form_field_options

Atomic data migration. Every options datum in the database — in
form_fields and form_field_library, their translations bags, and the
form_submissions.schema_snapshot + form_templates.schema_snapshot JSON
blobs — is converted to the new relational rich-shape representation.

Strict dispatch per §17.4.4 / §8.7 convention:
  - Fail on field_type ∉ {RADIO, SELECT, MULTISELECT, CHECKBOX_LIST}
    carrying non-null options (post-WS-5b TAG_PICKER seed-bug indicator)
  - Fail on non-flat-string-array options shape
  - Fail on translations.{locale}.options[] length mismatch
  - Fail on non-string / >255-char translated labels
  - Fail on any residual translations.{locale}.options key after
    step C migration

Snapshot rewrite in-place: both form_submissions.schema_snapshot and
form_templates.schema_snapshot walk fields[*] and rewrite options to
the new rich-shape, strip per-locale options[] from the parallel
translations bag. Zero-compromise directive — no reader tolerance for
pre-WS-5d shape in commit 3 onwards.

Rollback reconstructs JSON column shapes plus translations bags.
Forward+back pair safe as a unit; partial rollback unsupported.

FormFieldService::insertFromLibrary switches from JSON-copy to
FormFieldOptionService::copyOptions row-clone per addendum Q3 row-copy
mandate. The field's own translations bag no longer carries
{locale}.options keys — those live on option rows now.

Seeders and factories switch to service-level option creation:
  - FormBuilderDevSeeder.canonicalFields keeps flat-string options as
    its data shape; FormField::create no longer receives an options
    key, the post-create FormFieldOptionService::replaceOptions call
    inserts the rich rows. The same applies to
    seedEventRegistrationShowcaseSchema. The vergoedingstype field's
    legacy {label, description} object shape (a pre-WS-5d seed-bug
    that the strict backfill would reject) is normalised to flat
    strings; the descriptions are dropped.
  - seedSystemTemplates embeds rich-shape options in the template
    snapshot — no flat-array snapshot data remains in newly-seeded
    rows.
  - FormFieldFactory + FormFieldLibraryFactory drop the options
    default; new ::withOptions() helper accepts either flat strings
    (each becomes value+label) or full spec arrays and routes through
    the service.

JSON columns (form_fields.options, form_field_library.options) remain
present and writable via fillable; column-drop lands in commit 5.
Reads from the JSON column still exist in resources, snapshot writer,
FormRequests, FormValueService, and FilterRegistryController — commit
3 switches those all atomically.

Migration step-count tests in WS-5a/b/c bumped by 1 to account for
the new backfill_form_field_options migration on the migration stack.

Tests: 1182 → 1193 green (+11 tests / +56 assertions).

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

api/database/factories/FormBuilder/FormFieldLibraryFactory.php

@@ -11,6 +11,7 @@ use App\Models\FormBuilder\FormFieldBinding;
 use App\Models\FormBuilder\FormFieldLibrary;
 use App\Models\FormBuilder\FormFieldValidationRule;
 use App\Models\Organisation;
+use App\Services\FormBuilder\FormFieldOptionService;
 use Illuminate\Database\Eloquent\Factories\Factory;
 use Illuminate\Support\Str;
 
@@ -34,7 +35,6 @@ final class FormFieldLibraryFactory extends Factory
             'field_type' => FormFieldType::TEXT->value,
             'label' => fake('nl_NL')->words(2, true),
             'help_text' => null,
-            'options' => null,
             'default_is_required' => false,
             'default_is_filterable' => false,
             'translations' => null,
@@ -43,6 +43,34 @@ final class FormFieldLibraryFactory extends Factory
         ];
     }
 
+    /**
+     * Attach option rows in `form_field_options` after the library entry
+     * is persisted. Replaces populating the legacy `options` JSON column
+     * (WS-5d commit 2).
+     *
+     * @param  list<string|array{value:string,label:string,sort_order?:int,translations?:array<string,string>}>  $values
+     */
+    public function withOptions(array $values): static
+    {
+        return $this->afterCreating(function (FormFieldLibrary $library) use ($values): void {
+            $specs = [];
+            foreach (array_values($values) as $i => $entry) {
+                if (is_string($entry)) {
+                    $specs[] = ['value' => $entry, 'label' => $entry, 'sort_order' => $i];
+
+                    continue;
+                }
+                $specs[] = [
+                    'value' => (string) $entry['value'],
+                    'label' => (string) $entry['label'],
+                    'sort_order' => $entry['sort_order'] ?? $i,
+                    'translations' => $entry['translations'] ?? null,
+                ];
+            }
+            app(FormFieldOptionService::class)->replaceOptions($library, $specs);
+        });
+    }
+
     public function system(): static
     {
         return $this->state(fn () => ['is_system' => true]);