feat(admin): add admin scope management for users and events

- Introduced AdminScope enum for tenant and event scopes.
- Updated User model to include admin_scope and event_id attributes.
- Enhanced AdminAppAccessService to validate user scopes.
- Modified AdminAppMeResource and UserResource to include event data.
- Implemented middleware to ensure valid tenant access.
- Created migration to add admin_scope and event_id to users table.
- Added tests for event admin functionality and scope validation.

database/migrations/2026_09_30_000000_add_admin_scope_to_users.php

@@ -0,0 +1,25 @@
+<?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('users', function (Blueprint $table): void {
+            // Existing administrators keep their tenant-wide access.
+            $table->string('admin_scope', 20)->default('tenant');
+            $table->foreignId('event_id')->nullable()->constrained('events')->nullOnDelete();
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('users', function (Blueprint $table): void {
+            $table->dropConstrainedForeignId('event_id');
+            $table->dropColumn('admin_scope');
+        });
+    }
+};