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/Company.php

@@ -28,6 +28,7 @@ final class Company extends Model
         'organisation_id',
         'name',
         'type',
+        'handles_buma',
         'kvk_number',
         'contact_first_name',
         'contact_last_name',
@@ -35,6 +36,13 @@ final class Company extends Model
         'contact_phone',
     ];
 
+    protected function casts(): array
+    {
+        return [
+            'handles_buma' => 'boolean',
+        ];
+    }
+
     public function getContactFullNameAttribute(): ?string
     {
         if (! $this->contact_first_name) {
@@ -54,6 +62,11 @@ final class Company extends Model
         return $this->hasMany(Person::class);
     }
 
+    public function artistsAsAgent(): HasMany
+    {
+        return $this->hasMany(Artist::class, 'agent_company_id');
+    }
+
     /** @param Builder<self> $query */
     public function scopeOrdered(Builder $query): Builder
     {