feat(event): add rescheduling and cancellation state to event dates

database/migrations/2026_09_11_000000_add_rescheduling_state_to_event_dates.php

@@ -0,0 +1,30 @@
+<?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('event_dates', function (Blueprint $table): void {
+            $table->foreignId('rescheduled_to_event_date_id')
+                ->nullable()
+                ->after('validity_time_id')
+                ->constrained('event_dates')
+                ->restrictOnDelete();
+            $table->dateTime('cancelled_at')
+                ->nullable()
+                ->after('rescheduled_to_event_date_id');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('event_dates', function (Blueprint $table): void {
+            $table->dropConstrainedForeignId('rescheduled_to_event_date_id');
+            $table->dropColumn('cancelled_at');
+        });
+    }
+};