refactor(form-field): drop form_fields.options + form_field_library.options

Final WS-5d cleanup. The JSON columns that have been unread since
commit 3 are now physically dropped on both source tables. Their
canonical rich-shape lives in form_field_options, accessed
exclusively through the morphMany relation.

Defensive sweep: any lingering translations.{locale}.options key in
either source table's translations bag is stripped. Commit 2's
backfill should already have done so exhaustively; this is
belt-and-braces.

Rollback re-creates the columns as nullable JSON but leaves them
empty. Pair with commit 2's rollback to restore the pre-WS-5d data
shape on every owner row.

The commit-3 getOptionsAttribute accessor-bridge on FormField +
FormFieldLibrary is removed — Eloquent's getAttribute() resolution
now naturally falls through to the morphMany relation since there's
no underlying column to shadow it. New regression test
FormFieldOptionsAccessTest asserts $field->options resolves to an
Eloquent Collection of FormFieldOption instances and lazy-loads in
exactly 2 queries (1 parent + 1 lazy-load options) on a fresh fetch
without with() preload. Same trio for FormFieldLibrary.

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

Documentation:
  - SCHEMA.md v2.6: form_field_options table documented; options row
    removed from form_fields and form_field_library; morphMany
    relations updated; cross-references to ARCH-FORM-BUILDER §17.6
    and addendum §Q3 WS-5d Uitvoering added on both source-table
    docblocks.
  - ARCH-FORM-BUILDER.md v1.8: new §17.6 "Field options (relational)"
    mirrors the §17.4 / §17.5 relational-sibling structure with
    sub-sections 17.6.1 rationale, 17.6.2 table + catalogue, 17.6.3
    service / scope / cascade / activity log, 17.6.4 snapshot
    embedding, 17.6.5 external API contract. Existing Webhooks
    section renumbered from §17.6 to §17.7.
  - ARCH-CONSOLIDATION-ADDENDUM-2026-04-24.md: "Uitvoering — WS-5d
    (2026-04-27)" section added. Eight paragraphs covering the
    snapshot atomic rewrite, strict-fail backfill dispatch, dual
    activity-log emit, four-sibling base-class extraction warrant,
    commit 0 dead-code precondition, the temporary getOptionsAttribute
    accessor-bridge pattern (with reusability note for future
    JSON→relational refactors), the dev-seeder vergoedingstype RADIO
    normalisation (drift correction explicitly distinguished from the
    parallel apps/app RegistrationFieldTemplate description domain),
    and the WS-5 family completion note.
  - BACKLOG.md: FORM-BUILDER-LIBRARY-AUDIT-LOG entry extended to four
    services (adds library.options_replaced); new
    FORM-BUILDER-MORPH-SCOPE-BASE-CLASS entry added as the WS-5d
    follow-up now that all four concrete morph-scope siblings exist.

Tests: 1193 → 1208 green (+15 across commits 3+4+5; this commit alone:
+2 from the regression test).

This completes the WS-5 family.

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

api/tests/Feature/FormBuilder/ConditionalLogic/ConditionalLogicBackfillTest.php

@@ -31,11 +31,11 @@ final class ConditionalLogicBackfillTest extends TestCase
 
     public function test_forward_backfill_builds_nested_tree_from_legacy_json(): void
     {
-        // Roll back the WS-5d backfill-options + create-options + WS-5c
-        // drop-cl-col + WS-5c backfill-cl migrations to land in the
-        // conditional-logic JSON-era state with no relational
-        // form_field_options table yet.
-        $this->artisan('migrate:rollback', ['--step' => 4])->assertSuccessful();
+        // Roll back the WS-5d drop-options-cols + backfill-options +
+        // create-options + WS-5c drop-cl-col + WS-5c backfill-cl
+        // migrations to land in the conditional-logic JSON-era state with
+        // no relational form_field_options table yet.
+        $this->artisan('migrate:rollback', ['--step' => 5])->assertSuccessful();
         $this->assertTrue(Schema::hasColumn('form_fields', 'conditional_logic'));
 
         $fieldId = $this->seedFieldWithJson([
@@ -156,7 +156,7 @@ final class ConditionalLogicBackfillTest extends TestCase
         ]);
 
         // Roll back only the backfill migration — writes the JSON back.
-        $this->artisan('migrate:rollback', ['--step' => 4])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 5])->assertSuccessful();
 
         $reconstructed = DB::table('form_fields')
             ->where('id', $fieldId)
@@ -183,7 +183,7 @@ final class ConditionalLogicBackfillTest extends TestCase
 
     public function test_unknown_top_level_key_fails_migration(): void
     {
-        $this->artisan('migrate:rollback', ['--step' => 4])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 5])->assertSuccessful();
 
         $this->seedFieldWithJson([
             'hide_when' => ['all' => [['field_slug' => 'x', 'operator' => 'equals', 'value' => 1]]],
@@ -196,7 +196,7 @@ final class ConditionalLogicBackfillTest extends TestCase
 
     public function test_unknown_comparison_operator_fails_migration(): void
     {
-        $this->artisan('migrate:rollback', ['--step' => 4])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 5])->assertSuccessful();
 
         $this->seedFieldWithJson([
             'show_when' => ['all' => [['field_slug' => 'x', 'operator' => 'matches_regex', 'value' => 'y']]],