feat(form-builder): retry history table + integration (WS-6)

Per-attempt retry history (timestamp, user, outcome, exception detail
if failed) replaces the counter-only retry_count tracking.

Changes:

- New `form_submission_action_failure_retry_attempts` table (cascade on
  parent delete, nullOnDelete on user). Explicit short FK names
  (`fsafra_failure_fk`, `fsafra_user_fk`) — auto-generated names exceed
  MySQL's 64-char identifier limit.
- New FormSubmissionActionFailureRetryAttempt model + factory +
  succeeded() state.
- Parent FormSubmissionActionFailure gets retryAttempts() HasMany
  relation (latest('attempted_at')).
- New FormFailureRetryService centralises the retry-flow logic. Both
  the API controller and the artisan command delegate to it. Service
  writes a retry_attempt record per attempt; parent's retry_count
  stays as denormalised cache for index-view performance.
- Successful retry: attempt(succeeded) + parent.retry_count++ +
  parent.resolved_at + parent.resolved_by_user_id + parent.resolved_note
  ("Geslaagde retry door {actor.name}" or "Geslaagde retry
  (geautomatiseerd)" for command-line invocation without an actor).
- Failed retry: attempt(failed) with NEW exception details +
  parent.retry_count++. Parent's exception_class/_message stay
  audit-immutable — they represent the FIRST failure.
- canBeRetried() now correctly checks both resolved_at AND
  dismissed_at (sessie 2's open question Q2 closure).
- New FailureNotRetriableException (controller → 422) and
  ParentSubmissionGoneException (controller → 410) for cleaner
  flow control.

12 new tests:
- FormSubmissionActionFailureRetryAttemptTest (5 unit tests)
- RetryFlowProducesRetryAttemptsTest (7 integration tests covering
  succeeded path, failed path, resolved/dismissed blocking,
  multiple-retries chronological ordering, canBeRetried truth tables)

Pre-existing tests touched:
- FormSubmissionActionFailureTest::test_can_be_retried_only_for_open_state
  — updated to reflect Q2 closure (resolved now blocks too).
- Ws6FoundationMigrationTest::test_down_methods_clean_up_columns_and_table
  — child table must drop before parent (FK constraint).
- 5 backfill test step-counts bumped +1 (new migration sits at top).

SCHEMA.md → v2.9. Schema dump regenerated.

Refs: RFC-WS-6.md §3 Q5 addendum, sessie 2 Q2

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

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

@@ -49,7 +49,7 @@ final class ConditionalLogicBackfillTest extends TestCase
         // 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' => 8])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 9])->assertSuccessful();
         $this->assertTrue(Schema::hasColumn('form_fields', 'conditional_logic'));
 
         $fieldId = $this->seedFieldWithJson([
@@ -170,7 +170,7 @@ final class ConditionalLogicBackfillTest extends TestCase
         ]);
 
         // Roll back only the backfill migration — writes the JSON back.
-        $this->artisan('migrate:rollback', ['--step' => 8])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 9])->assertSuccessful();
 
         $reconstructed = DB::table('form_fields')
             ->where('id', $fieldId)
@@ -203,7 +203,7 @@ final class ConditionalLogicBackfillTest extends TestCase
 
     public function test_unknown_top_level_key_fails_migration(): void
     {
-        $this->artisan('migrate:rollback', ['--step' => 8])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 9])->assertSuccessful();
 
         $this->seedFieldWithJson([
             'hide_when' => ['all' => [['field_slug' => 'x', 'operator' => 'equals', 'value' => 1]]],
@@ -216,7 +216,7 @@ final class ConditionalLogicBackfillTest extends TestCase
 
     public function test_unknown_comparison_operator_fails_migration(): void
     {
-        $this->artisan('migrate:rollback', ['--step' => 8])->assertSuccessful();
+        $this->artisan('migrate:rollback', ['--step' => 9])->assertSuccessful();
 
         $this->seedFieldWithJson([
             'show_when' => ['all' => [['field_slug' => 'x', 'operator' => 'matches_regex', 'value' => 'y']]],