feat(events): associate purchases and integrations with events

tests/Feature/Migrations/AddEventIdToPurchasesTest.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace Tests\Feature\Migrations;
+
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+use Tests\TestCase;
+
+class AddEventIdToPurchasesTest extends TestCase
+{
+    public function test_it_backfills_the_event_from_purchase_items(): void
+    {
+        Schema::create('events', fn (Blueprint $table) => $table->id());
+        Schema::create('compras', fn (Blueprint $table) => $table->id());
+        Schema::create('catalog_items', function (Blueprint $table): void {
+            $table->id();
+            $table->foreignId('event_id')->nullable();
+        });
+        Schema::create('compra_items', function (Blueprint $table): void {
+            $table->id();
+            $table->foreignId('compra_id');
+            $table->foreignId('source_catalog_item_id');
+        });
+
+        DB::table('events')->insert([['id' => 10], ['id' => 11]]);
+        DB::table('compras')->insert([['id' => 20], ['id' => 21]]);
+        DB::table('catalog_items')->insert([
+            ['id' => 30, 'event_id' => 10],
+            ['id' => 31, 'event_id' => 11],
+        ]);
+        DB::table('compra_items')->insert([
+            ['compra_id' => 20, 'source_catalog_item_id' => 30],
+            ['compra_id' => 21, 'source_catalog_item_id' => 30],
+            ['compra_id' => 21, 'source_catalog_item_id' => 31],
+        ]);
+
+        $migration = require database_path('migrations/2026_09_28_000100_add_event_id_to_compras.php');
+        $migration->up();
+
+        $this->assertDatabaseHas('compras', ['id' => 20, 'event_id' => 10]);
+        $this->assertDatabaseHas('compras', ['id' => 21, 'event_id' => null]);
+    }
+}