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/FormSubmission.php

@@ -0,0 +1,102 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models\FormBuilder;
+
+use App\Enums\FormBuilder\FormSubmissionReviewStatus;
+use App\Enums\FormBuilder\FormSubmissionStatus;
+use App\Models\User;
+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\Relations\MorphTo;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+/**
+ * No direct activity-log hooks on this model: lifecycle events fire from the
+ * FormSubmissionService (arriving in S2) per ARCH §17.1.
+ */
+final class FormSubmission extends Model
+{
+    use HasFactory;
+    use HasUlids;
+    use SoftDeletes;
+
+    protected $fillable = [
+        'form_schema_id',
+        'subject_type',
+        'subject_id',
+        'submitted_by_user_id',
+        'public_submitter_name',
+        'public_submitter_email',
+        'public_submitter_ip',
+        'public_submitter_ip_anonymised_at',
+        'status',
+        'review_status',
+        'reviewed_by_user_id',
+        'reviewed_at',
+        'review_notes',
+        'submitted_at',
+        'schema_snapshot',
+        'is_test',
+        'submitted_in_locale',
+        'opened_at',
+        'first_interacted_at',
+        'idempotency_key',
+    ];
+
+    /** @var array<string, string> */
+    protected $casts = [
+        'status' => FormSubmissionStatus::class,
+        'review_status' => FormSubmissionReviewStatus::class,
+        'schema_snapshot' => 'array',
+        'is_test' => 'bool',
+        'submitted_at' => 'datetime',
+        'reviewed_at' => 'datetime',
+        'anonymised_at' => 'datetime',
+        'opened_at' => 'datetime',
+        'first_interacted_at' => 'datetime',
+        'public_submitter_ip_anonymised_at' => 'datetime',
+        'schema_version_at_submit' => 'int',
+        'submission_duration_seconds' => 'int',
+        'auto_save_count' => 'int',
+    ];
+
+    public function schema(): BelongsTo
+    {
+        return $this->belongsTo(FormSchema::class, 'form_schema_id');
+    }
+
+    public function subject(): MorphTo
+    {
+        return $this->morphTo();
+    }
+
+    public function submittedBy(): BelongsTo
+    {
+        return $this->belongsTo(User::class, 'submitted_by_user_id');
+    }
+
+    public function reviewedBy(): BelongsTo
+    {
+        return $this->belongsTo(User::class, 'reviewed_by_user_id');
+    }
+
+    public function values(): HasMany
+    {
+        return $this->hasMany(FormValue::class);
+    }
+
+    public function sectionStatuses(): HasMany
+    {
+        return $this->hasMany(FormSubmissionSectionStatus::class);
+    }
+
+    public function delegations(): HasMany
+    {
+        return $this->hasMany(FormSubmissionDelegation::class);
+    }
+}