feat(ticketing): resolve validity in tenant timezone

database/migrations/2026_09_21_040000_add_timezone_to_tenants.php

@@ -0,0 +1,41 @@
+<?php
+
+use Carbon\CarbonImmutable;
+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('tenants', function (Blueprint $table): void {
+            $table->string('timezone')->default('America/Argentina/Buenos_Aires');
+        });
+
+        // Correct legacy event windows once, using their original local date and hours.
+        // Subsequent tenant timezone changes do not rewrite stored UTC instants.
+        DB::table('event_dates')->orderBy('id')->chunkById(200, function ($dates): void {
+            foreach ($dates as $date) {
+                $timezone = DB::table('tenants')->where('codigo', $date->tenant_code)->value('timezone');
+                $start = CarbonImmutable::parse(substr($date->date, 0, 10).' '.$date->time_start, $timezone);
+                $end = CarbonImmutable::parse(substr($date->date, 0, 10).' '.$date->time_end, $timezone);
+                if ($end->lessThanOrEqualTo($start)) {
+                    $end = $end->addDay();
+                }
+                DB::table('validity_times')->where('id', $date->validity_time_id)->update([
+                    'fixed_starts_at' => $start->utc()->format('Y-m-d H:i:s'),
+                    'fixed_expires_at' => $end->utc()->format('Y-m-d H:i:s'),
+                ]);
+            }
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('tenants', function (Blueprint $table): void {
+            $table->dropColumn('timezone');
+        });
+    }
+};