feat(forms): add Eloquent models, observer, events, activity-log helpers

Phase 4 of S1.

Models (app/Models/FormBuilder/): FormSchema, FormSchemaSection, FormField,
FormSubmission, FormValue, FormValueOption, FormTemplate, FormFieldLibrary,
FormSchemaWebhook, FormWebhookDelivery, FormSubmissionSectionStatus,
FormSubmissionDelegation. Plus UserProfile at app/Models/ (user-universal).

OrganisationScope applied on: FormSchema, FormTemplate, FormFieldLibrary.
FormSchemaWebhook documents inherited-scope discipline (OrganisationScope's
strategies — organisation_id/event_id/festival_section_id — don't cover
form_schema_id; direct queries would leak across orgs, so must go via
$schema->webhooks()).

User::profile()/getOrCreateProfile(), Event::formSchemas() (morphMany),
Person::formSubmissions() (morphMany).

Morph map enforced in AppServiceProvider with 28 keys covering every model
that appears as activitylog subject/causer. Also updated
OrganisationDashboardService (and its test) to query activitylog via
getMorphClass() instead of FQCN.

Activity log strategy: nuanced explicit calls (logSchemaChange on FormSchema,
logFieldChange on FormField) — no LogsActivity trait. Suppression for bulk
fixtures via App\Support\ActivityLog::suppressed(fn() => ...) which flips
config('activitylog.enabled') around a callback. Both our explicit calls
and spatie's trait on Organisation respect the flag via ActivityLogger::log().

FormValueObserver (app/Observers/FormBuilder/) populates value_indexed/
value_number/value_date/value_bool on save per field.value_storage_hint,
rebuilds form_value_options pivot on multi-value filterable fields, cleans
up on delete. Memoised field cache avoids N+1. Registered in AppServiceProvider.

9 lightweight event classes (app/Events/FormBuilder/) as SerializesModels
containers — submission lifecycle signatures lock in for S2 services, no
listeners yet.

Factories for all models with Dutch fake data (fake('nl_NL')). FormSchema
factory uses defaultSubmissionMode(); FormField factory uses
recommendedValueStorageHint().

Tests: 9 new observer tests (all pass); full suite 910/910 (up from 901).

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

api/app/Support/ActivityLog.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Support;
+
+/**
+ * Dev-only helper for suppressing activity-log writes during bulk fixture
+ * runs (DevSeeder, data-migration commands). Flips spatie's global
+ * `activitylog.enabled` config key for the duration of the callback and
+ * restores whatever it was before.
+ *
+ * Suppresses BOTH our explicit calls (FormSchema::logSchemaChange etc.)
+ * AND spatie's LogsActivity trait on Organisation — both respect the
+ * `activitylog.enabled` config key via ActivityLogger::log().
+ *
+ * Do NOT use in production request paths. Intended for artisan commands.
+ */
+final class ActivityLog
+{
+    /**
+     * @template T
+     *
+     * @param  callable(): T  $callback
+     * @return T
+     */
+    public static function suppressed(callable $callback): mixed
+    {
+        $previous = config('activitylog.enabled');
+        config(['activitylog.enabled' => false]);
+
+        try {
+            return $callback();
+        } finally {
+            config(['activitylog.enabled' => $previous]);
+        }
+    }
+}