feat(timetable): Artist domain — 7 enums + 9 Eloquent models

Enums under App\Enums\Artist\ (PascalCase per FormBuilder convention,
snake_case wire values per RFC):
- ArtistEngagementStatus (D9, 9 states + Dutch labels)
- BumaHandledBy (D26)
- FeeType, PaymentStatus
- AdvanceSectionType, AdvanceSectionSubmissionStatus, AdvanceSubmissionStatus

Models:
- Artist (org-scoped, slug-unique-per-org via creating boot hook)
- ArtistEngagement (per-event booking, denorm organisation_id)
- Genre, Stage (event-scoped, ordered scope), StageDay (Pivot, int PK)
- Performance (engagement-scoped, isParked() helper)
- AdvanceSection, AdvanceSubmission, ArtistContact (primary scope)

OrganisationScope wired:
- Direct organisation_id: Artist, Genre, ArtistEngagement
- FK-chain via tenantScopeStrategy(): Stage→Event, Performance→Engagement,
  AdvanceSection→Engagement, AdvanceSubmission→Section→Engagement,
  ArtistContact→Artist, StageDay→Stage→Event

Soft-deletes: Artist, ArtistEngagement, Performance (per RFC §5.4).
LogsActivity baseline (logFillable+dontSubmitEmptyLogs) on all business
models — actual mutation surfaces wire LogOptions in Session 2+.

Inverse relations added on Organisation, Event, Company.
companies.handles_buma cast added.

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

api/app/Models/AdvanceSection.php

@@ -0,0 +1,79 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use App\Enums\Artist\AdvanceSectionSubmissionStatus;
+use App\Enums\Artist\AdvanceSectionType;
+use App\Models\Scopes\OrganisationScope;
+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 Spatie\Activitylog\Models\Concerns\LogsActivity;
+use Spatie\Activitylog\Support\LogOptions;
+
+final class AdvanceSection extends Model
+{
+    use HasFactory;
+    use HasUlids;
+    use LogsActivity;
+
+    protected static function booted(): void
+    {
+        self::addGlobalScope(new OrganisationScope);
+    }
+
+    /** @return array{via: class-string, fk: string} */
+    public static function tenantScopeStrategy(): array
+    {
+        return ['via' => ArtistEngagement::class, 'fk' => 'engagement_id'];
+    }
+
+    protected $fillable = [
+        'engagement_id',
+        'name',
+        'type',
+        'is_open',
+        'open_from',
+        'open_to',
+        'sort_order',
+        'submission_status',
+        'last_submitted_at',
+        'last_submitted_by',
+        'submission_diff',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'type' => AdvanceSectionType::class,
+            'submission_status' => AdvanceSectionSubmissionStatus::class,
+            'is_open' => 'boolean',
+            'open_from' => 'datetime',
+            'open_to' => 'datetime',
+            'sort_order' => 'integer',
+            'last_submitted_at' => 'datetime',
+            'submission_diff' => 'array',
+        ];
+    }
+
+    public function getActivitylogOptions(): LogOptions
+    {
+        return LogOptions::defaults()
+            ->logFillable()
+            ->dontSubmitEmptyLogs();
+    }
+
+    public function engagement(): BelongsTo
+    {
+        return $this->belongsTo(ArtistEngagement::class, 'engagement_id');
+    }
+
+    public function submissions(): HasMany
+    {
+        return $this->hasMany(AdvanceSubmission::class);
+    }
+}