feat: add platform public question bank workspace

Tiku.Infrastructure/Bootstrap/BuiltinBackofficeCatalogSeeder.cs

@@ -1,5 +1,6 @@
 using Microsoft.EntityFrameworkCore;
 using Tiku.Application.Security;
+using Tiku.Domain.Common;
 using Tiku.Domain.Operations;
 using Tiku.Domain.Platform;
 using Tiku.Domain.Tenancy;
@@ -124,6 +125,21 @@ public sealed class BuiltinBackofficeCatalogSeeder(TikuDbContext dbContext)
 
     public async Task SeedAsync(CancellationToken cancellationToken = default)
     {
+        var platformOwnedTenant = await dbContext.Tenants
+            .SingleOrDefaultAsync(item => item.Mode == TenantMode.PlatformOwned, cancellationToken);
+        if (platformOwnedTenant is null)
+        {
+            dbContext.Tenants.Add(new Tenant
+            {
+                Slug = "platform-public-content",
+                Name = "平台公共内容",
+                Status = TenantStatus.Active,
+                Mode = TenantMode.PlatformOwned,
+                BillingStatus = BillingStatus.Active,
+                Metadata = JsonDefaults.Object()
+            });
+        }
+
         var featureCodes = Features.Select(item => item.Code).ToArray();
         var existingFeatureCodes = await dbContext.SaasFeatures.AsNoTracking()
             .Where(item => featureCodes.Contains(item.Code))