feat(event): add per-user date change notices

database/migrations/2026_09_15_000000_create_user_event_date_change_views_table.php

@@ -0,0 +1,27 @@
+<?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::create('user_event_date_change_views', function (Blueprint $table): void {
+            $table->id();
+            $table->foreignId('user_id')->constrained('users')->cascadeOnDelete();
+            $table->foreignId('event_date_change_id')->constrained('event_date_changes')->cascadeOnDelete();
+            $table->unsignedTinyInteger('display_count')->default(0);
+            $table->timestamp('last_displayed_at')->nullable();
+            $table->timestamps();
+
+            $table->unique(['user_id', 'event_date_change_id']);
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('user_event_date_change_views');
+    }
+};