feat: add support for multiple event dates in variants

- Updated the FeaturedGroupService to include 'variants.eventDates' in the items query.
- Introduced a BelongsToMany relationship in EventDate for selected variants.
- Modified PurchaseItemResource and PurchaseItemSnapshotFactory to handle multiple event dates for variants.
- Enhanced StartCheckoutService to load event dates for variants.
- Updated TicketGeneratorService to accommodate event dates in ticket generation.
- Created migrations to support multi-value event dates and allow multiple variant values per attribute.
- Adjusted seeders to reflect new event date handling and added new attributes.
- Added tests to ensure correct functionality for multi-date variants and their integration with ticket generation.

database/migrations/2026_08_07_000300_add_multi_value_event_dates_to_variants.php

@@ -0,0 +1,42 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::table('item_attributes', function (Blueprint $table): void {
+            $table->boolean('allow_multi_select')->default(false)->after('attribute_id');
+        });
+
+        Schema::create('variant_event_dates', function (Blueprint $table): void {
+            $table->foreignId('variant_id')->constrained('variantes')->cascadeOnDelete();
+            $table->foreignId('event_date_id')->constrained('event_dates')->cascadeOnDelete();
+            $table->primary(['variant_id', 'event_date_id']);
+            $table->index(['event_date_id', 'variant_id']);
+        });
+
+        DB::table('variantes')
+            ->whereNotNull('event_date_id')
+            ->orderBy('id')
+            ->each(function (object $variant): void {
+                DB::table('variant_event_dates')->insertOrIgnore([
+                    'variant_id' => $variant->id,
+                    'event_date_id' => $variant->event_date_id,
+                ]);
+            });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('variant_event_dates');
+
+        Schema::table('item_attributes', function (Blueprint $table): void {
+            $table->dropColumn('allow_multi_select');
+        });
+    }
+};

database/migrations/2026_08_07_000400_allow_multiple_variant_values_per_attribute.php

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+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::table('variant_values', function (Blueprint $table): void {
+            $table->dropUnique('variant_values_variant_id_item_attribute_id_unique');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('variant_values', function (Blueprint $table): void {
+            $table->unique(['variant_id', 'item_attribute_id']);
+        });
+    }
+};