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/tests/Feature/FormBuilder/ValidationRules/FormFieldValidationRuleBackfillTest.php

@@ -31,15 +31,15 @@ final class FormFieldValidationRuleBackfillTest extends TestCase
 
     public function test_forward_migration_backfills_rows_with_field_type_dispatch(): void
     {
-        // Roll back: 1 WS-5d migration (create-options) +
+        // Roll back: 2 WS-5d migrations (backfill-options, create-options) +
         // 4 WS-5c migrations (drop-conditional-logic-col,
         // backfill-conditional-logic, create-conditional-logic-conditions,
         // create-conditional-logic-groups) + 5 WS-5b migrations
         // (drop-cols + configs-backfill + create-configs +
-        // validation-rules-backfill + create-validation-rules) = 10.
+        // validation-rules-backfill + create-validation-rules) = 11.
         // Brings us to the pre-WS-5b state: validation_rules JSON column
         // present, no relational tables for WS-5b/c/d.
-        $this->artisan('migrate:rollback', ['--step' => 10])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 11])->assertSuccessful();
         $this->assertFalse(Schema::hasTable('form_field_validation_rules'));
         $this->assertTrue(Schema::hasColumn('form_fields', 'validation_rules'));
 
@@ -100,7 +100,7 @@ final class FormFieldValidationRuleBackfillTest extends TestCase
         // (validation_rules JSON column present; no relational tables for
         // WS-5b). Step count: drop-cols + configs-backfill + create-configs
         // + validation-rules-backfill + create-validation-rules = 5.
-        $this->artisan('migrate:rollback', ['--step' => 10])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 11])->assertSuccessful();
 
         $fieldId = $this->seedFieldWithJson([
             'field_type' => 'TAG_PICKER',
@@ -124,7 +124,7 @@ final class FormFieldValidationRuleBackfillTest extends TestCase
         // (validation_rules JSON column present; no relational tables for
         // WS-5b). Step count: drop-cols + configs-backfill + create-configs
         // + validation-rules-backfill + create-validation-rules = 5.
-        $this->artisan('migrate:rollback', ['--step' => 10])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 11])->assertSuccessful();
 
         $fieldId = $this->seedFieldWithJson([
             'field_type' => 'TEXT',
@@ -151,7 +151,7 @@ final class FormFieldValidationRuleBackfillTest extends TestCase
         // (validation_rules JSON column present; no relational tables for
         // WS-5b). Step count: drop-cols + configs-backfill + create-configs
         // + validation-rules-backfill + create-validation-rules = 5.
-        $this->artisan('migrate:rollback', ['--step' => 10])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 11])->assertSuccessful();
 
         $this->seedFieldWithJson([
             'field_type' => 'TEXT',
@@ -168,7 +168,7 @@ final class FormFieldValidationRuleBackfillTest extends TestCase
         // (validation_rules JSON column present; no relational tables for
         // WS-5b). Step count: drop-cols + configs-backfill + create-configs
         // + validation-rules-backfill + create-validation-rules = 5.
-        $this->artisan('migrate:rollback', ['--step' => 10])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 11])->assertSuccessful();
 
         $this->seedFieldWithJson([
             'field_type' => 'BOOLEAN',
@@ -187,7 +187,7 @@ final class FormFieldValidationRuleBackfillTest extends TestCase
         // full-back-then-full-forward cycle — rolling back all WS-5b
         // migrations restores the pre-WS-5b state (columns present on
         // source tables; validation rules relational table gone).
-        $this->artisan('migrate:rollback', ['--step' => 10])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 11])->assertSuccessful();
         [$numberId] = $this->seedFields();
 
         $this->artisan('migrate')->assertSuccessful();
@@ -202,7 +202,7 @@ final class FormFieldValidationRuleBackfillTest extends TestCase
 
         // Roll back WS-5b fully → column reappears and carries canonical JSON
         // reconstructed from the relational rows.
-        $this->artisan('migrate:rollback', ['--step' => 10])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 11])->assertSuccessful();
         $this->assertTrue(Schema::hasColumn('form_fields', 'validation_rules'));
 
         $field = DB::table('form_fields')->where('id', $numberId)->first();