feat(form-builder): add FormSubmissionActionFailure model + apply_status casts (WS-6)

- FormSubmissionActionFailure: audit model, no organisation_id (FK-chain
  tenancy per RFC V3), open/resolved/dismissed scopes, canBeRetried()
  helper. Morph alias 'form_submission_action_failure' registered for
  future activity-log subject references.
- FormSubmission: apply_status (ApplyStatus enum cast),
  apply_completed_at (datetime), actionFailures() HasMany,
  scopePendingApply().

Refs: RFC-WS-6.md §3 (Q5), §4 (V3)

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

api/database/factories/FormBuilder/FormSubmissionActionFailureFactory.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Database\Factories\FormBuilder;
+
+use App\Models\FormBuilder\FormSubmission;
+use App\Models\FormBuilder\FormSubmissionActionFailure;
+use Illuminate\Database\Eloquent\Factories\Factory;
+
+/** @extends Factory<FormSubmissionActionFailure> */
+final class FormSubmissionActionFailureFactory extends Factory
+{
+    protected $model = FormSubmissionActionFailure::class;
+
+    /** @return array<model-property<FormSubmissionActionFailure>, mixed> */
+    public function definition(): array
+    {
+        return [
+            'form_submission_id' => FormSubmission::factory(),
+            'listener_class' => 'App\\Listeners\\FormBuilder\\ApplyBindingsOnFormSubmit',
+            'binding_id' => null,
+            'failed_at' => now(),
+            'exception_class' => \RuntimeException::class,
+            'exception_message' => 'Simulated apply failure',
+            'context' => [
+                'target_entity' => 'person',
+                'target_attribute' => 'email',
+            ],
+            'retry_count' => 0,
+            'resolved_at' => null,
+            'resolved_by_user_id' => null,
+            'resolved_note' => null,
+            'dismissed_at' => null,
+            'dismissed_by_user_id' => null,
+            'dismissed_reason_type' => null,
+            'dismissed_reason_note' => null,
+        ];
+    }
+
+    public function resolved(): static
+    {
+        return $this->state(fn (): array => [
+            'resolved_at' => now(),
+            'resolved_note' => 'Resolved via direct edit',
+        ]);
+    }
+
+    public function dismissed(): static
+    {
+        return $this->state(fn (): array => [
+            'dismissed_at' => now(),
+            'dismissed_reason_type' => \App\Enums\FormBuilder\DismissalReasonType::SCHEMA_DELETED,
+        ]);
+    }
+}