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/Enums/Artist/PaymentStatus.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Enums\Artist;
+
+/**
+ * Payment progress for an ArtistEngagement.
+ *
+ * Per RFC-TIMETABLE v0.2 §5.3 (`payment_status` column).
+ */
+enum PaymentStatus: string
+{
+    case None = 'none';
+    case DepositPaid = 'deposit_paid';
+    case PaidInFull = 'paid_in_full';
+
+    public function label(): string
+    {
+        return match ($this) {
+            self::None => 'Geen betaling',
+            self::DepositPaid => 'Aanbetaling voldaan',
+            self::PaidInFull => 'Volledig voldaan',
+        };
+    }
+}