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/Models/FormBuilder/FormField.php

@@ -0,0 +1,120 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models\FormBuilder;
+
+use App\Enums\FormBuilder\FormFieldDisplayWidth;
+use App\Enums\FormBuilder\FormValueStorageHint;
+use Illuminate\Database\Eloquent\Concerns\HasUlids;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+/**
+ * Activity log strategy: explicit calls via logFieldChange() — no LogsActivity
+ * trait. Logged events: create/delete/restore, field_type change, binding
+ * change, is_pii/is_filterable toggle, structural options change.
+ * See ARCH-FORM-BUILDER.md §17.1 and S1 Phase 4b.
+ *
+ * field_type is stored as string (not DB enum) so CustomFieldTypeRegistry
+ * (ARCH §17.2) can extend it at runtime.
+ */
+final class FormField extends Model
+{
+    use HasFactory;
+    use HasUlids;
+    use SoftDeletes;
+
+    protected $fillable = [
+        'form_schema_id',
+        'form_schema_section_id',
+        'library_field_id',
+        'field_type',
+        'slug',
+        'label',
+        'help_text',
+        'section',
+        'options',
+        'validation_rules',
+        'is_required',
+        'is_filterable',
+        'is_portal_visible',
+        'is_admin_only',
+        'is_unique',
+        'is_pii',
+        'display_width',
+        'binding',
+        'conditional_logic',
+        'role_restrictions',
+        'translations',
+        'value_storage_hint',
+        'review_required',
+        'sort_order',
+    ];
+
+    /** @var array<string, string> */
+    protected $casts = [
+        'options' => 'array',
+        'validation_rules' => 'array',
+        'binding' => 'array',
+        'conditional_logic' => 'array',
+        'role_restrictions' => 'array',
+        'translations' => 'array',
+        'is_required' => 'bool',
+        'is_filterable' => 'bool',
+        'is_portal_visible' => 'bool',
+        'is_admin_only' => 'bool',
+        'is_unique' => 'bool',
+        'is_pii' => 'bool',
+        'review_required' => 'bool',
+        'display_width' => FormFieldDisplayWidth::class,
+        'value_storage_hint' => FormValueStorageHint::class,
+        'sort_order' => 'int',
+    ];
+
+    public function schema(): BelongsTo
+    {
+        return $this->belongsTo(FormSchema::class, 'form_schema_id');
+    }
+
+    public function section(): BelongsTo
+    {
+        return $this->belongsTo(FormSchemaSection::class, 'form_schema_section_id');
+    }
+
+    public function libraryField(): BelongsTo
+    {
+        return $this->belongsTo(FormFieldLibrary::class, 'library_field_id');
+    }
+
+    public function values(): HasMany
+    {
+        return $this->hasMany(FormValue::class);
+    }
+
+    /**
+     * Nuanced activity log (ARCH §17.1; S1 Phase 4b). Callers choose which
+     * events are worth logging — e.g. created/deleted/restored, field_type
+     * changed (value storage changes), binding changed, is_pii toggled,
+     * is_filterable toggled (triggers backfill), structural options changes.
+     * NOT logged (noise): label/help_text/sort_order/conditional_logic/
+     * translations.
+     *
+     * Bulk-fixture suppression: the activitylog.enabled config key is the
+     * kill-switch. Seeders and one-shot commands wrap themselves in
+     * App\Support\ActivityLog::suppressed(...). activity()->log() becomes
+     * a silent no-op while disabled, so no guard is needed here.
+     *
+     * @param  array<string, mixed>  $properties
+     */
+    public function logFieldChange(string $event, array $properties = []): void
+    {
+        activity()
+            ->performedOn($this)
+            ->withProperties($properties)
+            ->log($event);
+    }
+}