test(forms): model tests, multi-tenancy, migration rollback (Phase 9)

UserProfileTest: belongs-to user, fillable/non-fillable boundaries,
settings cast, lastSubmittedAt accessor (null + max from user-subject
submissions only, ignoring drafts and is_test rows).

FormSchemaTest: ULID PK, OrganisationScope filtering, polymorphic owner
resolution to Event, purpose enum cast, hasMany fields/submissions, and
logSchemaChange() actually creates an activity-log entry.

FormFieldTest: belongs-to schema, field_type stored as string (not DB
enum), binding/translations array casts, hasMany values, soft-delete
preserves historical values, logFieldChange() creates an entry.

FormSubmissionTest: belongs-to schema, polymorphic subject resolution,
status enum cast, schema_snapshot array cast, hasMany values.

FormValueTest: belongs-to submission/field, value array cast, hasMany
options pivot rebuilt by observer, unique-pair DB constraint enforced.

MultiTenancyTest: OrganisationScope correctly filters FormSchema /
FormTemplate / FormFieldLibrary by route-resolved organisation. Pins
the FormSchemaWebhook un-scoped behaviour explicitly so a future scope
addition is an intentional decision, not an accident.

MigrationRollbackTest (group 'slow'): full migrate:fresh → rollback 14
S1 steps → assert all 13 form-builder tables dropped + legacy tables
intentionally retained → re-migrate and assert table list matches
snapshot. Plus a separate test exercising the populate-user-profiles
migration's down().

Supporting tweaks:
- UserProfile::lastSubmittedAt accessor now returns Carbon|null instead
  of a raw timestamp string — testable, and matches Eloquent convention.
- UserProfileFactory cooperates with UserObserver via newModel override
  (updates the auto-created row instead of inserting a duplicate).
- AppServiceProvider morph map extended with all 12 form-builder model
  keys so logSchemaChange/logFieldChange resolve under enforceMorphMap.

Suite: 945 passed (was 911), 2671 assertions.

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

api/app/Providers/AppServiceProvider.php

@@ -34,7 +34,18 @@ use App\Models\User;
 use App\Models\UserInvitation;
 use App\Models\UserOrganisationTag;
 use App\Models\UserProfile;
+use App\Models\FormBuilder\FormField;
+use App\Models\FormBuilder\FormFieldLibrary;
+use App\Models\FormBuilder\FormSchema;
+use App\Models\FormBuilder\FormSchemaSection;
+use App\Models\FormBuilder\FormSchemaWebhook;
+use App\Models\FormBuilder\FormSubmission;
+use App\Models\FormBuilder\FormSubmissionDelegation;
+use App\Models\FormBuilder\FormSubmissionSectionStatus;
+use App\Models\FormBuilder\FormTemplate;
 use App\Models\FormBuilder\FormValue;
+use App\Models\FormBuilder\FormValueOption;
+use App\Models\FormBuilder\FormWebhookDelivery;
 use App\Models\VolunteerAvailability;
 use App\Observers\FormBuilder\FormValueObserver;
 use App\Observers\PersonObserver;
@@ -95,6 +106,22 @@ class AppServiceProvider extends ServiceProvider
             'user_invitation' => UserInvitation::class,
             'user_organisation_tag' => UserOrganisationTag::class,
             'volunteer_availability' => VolunteerAvailability::class,
+
+            // Form-builder models — used as activity-log subjects via the
+            // logSchemaChange / logFieldChange helpers, and (in S2+) as
+            // polymorphic webhook payload subjects.
+            'form_schema' => FormSchema::class,
+            'form_schema_section' => FormSchemaSection::class,
+            'form_field' => FormField::class,
+            'form_field_library' => FormFieldLibrary::class,
+            'form_submission' => FormSubmission::class,
+            'form_submission_section_status' => FormSubmissionSectionStatus::class,
+            'form_submission_delegation' => FormSubmissionDelegation::class,
+            'form_value' => FormValue::class,
+            'form_value_option' => FormValueOption::class,
+            'form_template' => FormTemplate::class,
+            'form_schema_webhook' => FormSchemaWebhook::class,
+            'form_webhook_delivery' => FormWebhookDelivery::class,
         ]);
 
         Person::observe(PersonObserver::class);