feat: refactor super admin to use is_super_admin flag and enhance site deletion logic

- Changed super admin detection from role-based to `is_super_admin` flag in AdminUser model
- Added `requireDefaultAdminSiteId()` method to throw validation error when no integration site exists
- Enhanced site deletion to migrate platform role bindings to fallback site and auto-delete site-specific admin accounts
- Made agent line code optional with auto-generation fallback using `{site_code}-agent-{counter}` format

tests/Feature/AdminSiteDashboardOverviewTest.php

@@ -0,0 +1,70 @@
+<?php
+
+use App\Models\AdminSite;
+use App\Models\AdminUser;
+use App\Support\AdminAuthProfile;
+use App\Support\SitePlatformRole;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Hash;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function (): void {
+    $this->artisan('lottery:admin-auth-sync')->assertExitCode(0);
+});
+
+test('site admin dashboard returns site overview for operator with dashboard permission', function (): void {
+    $super = AdminUser::query()->create([
+        'username' => 'super_site_dash',
+        'name' => 'Super',
+        'email' => null,
+        'password' => Hash::make('secret-strong'),
+        'status' => 0,
+    ]);
+    grantSuperAdminRole($super);
+
+    $token = $super->createToken('test', ['*'], now()->addDay())->plainTextToken;
+
+    $create = $this->withHeader('Authorization', 'Bearer '.$token)
+        ->postJson('/api/v1/admin/integration-sites', [
+            'code' => 'site-dash',
+            'name' => 'Site Dash',
+            'admin_account' => [
+                'username' => 'site_dash_admin',
+                'nickname' => 'Site Dash Admin',
+                'password' => 'secret-strong',
+            ],
+        ])
+        ->assertCreated();
+
+    $siteId = (int) $create->json('data.id');
+    $operator = AdminUser::query()->where('username', 'site_dash_admin')->firstOrFail();
+    $roleId = SitePlatformRole::id();
+
+    expect((int) DB::table('admin_user_site_roles')
+        ->where('admin_user_id', $operator->id)
+        ->where('site_id', $siteId)
+        ->where('role_id', $roleId)
+        ->count())->toBe(1);
+
+    expect(SitePlatformRole::userHasSiteAdminRole($operator))->toBeTrue();
+    expect(AdminAuthProfile::fromAdmin($operator)['site']['code'] ?? null)->toBe('site-dash');
+
+    $operatorToken = $operator->createToken('test', ['*'], now()->addDay())->plainTextToken;
+    app('auth')->forgetGuards();
+
+    $this->withHeader('Authorization', 'Bearer '.$operatorToken)
+        ->getJson('/api/v1/admin/auth/me')
+        ->assertOk()
+        ->assertJsonPath('data.admin.id', $operator->id)
+        ->assertJsonPath('data.admin.site.code', 'site-dash')
+        ->assertJsonPath('data.admin.agent', null);
+
+    $this->withHeader('Authorization', 'Bearer '.$operatorToken)
+        ->getJson('/api/v1/admin/dashboard')
+        ->assertOk()
+        ->assertJsonPath('data.site_overview.admin_site_id', $siteId)
+        ->assertJsonPath('data.site_overview.site_code', 'site-dash')
+        ->assertJsonPath('data.agent_overview', null);
+});