feat(templates): add service language template management

Add normalized service and template catalogs, scoped administration, migration, validation, and regression coverage.

Ref: IT-1601

HrynCo.NotificationService.Migrator/DevelopmentDataSeeder.cs

@@ -12,15 +12,18 @@ internal sealed class DevelopmentDataSeeder
 
     private readonly IEmailChannelRepository _channels;
     private readonly IEmailTemplateRepository _templates;
+    private readonly INotificationServiceRepository _services;
     private readonly ILogger<DevelopmentDataSeeder> _logger;
 
     public DevelopmentDataSeeder(
         IEmailChannelRepository channels,
         IEmailTemplateRepository templates,
+        INotificationServiceRepository services,
         ILogger<DevelopmentDataSeeder> logger)
     {
         _channels = channels;
         _templates = templates;
+        _services = services;
         _logger = logger;
     }
 
@@ -30,6 +33,7 @@ internal sealed class DevelopmentDataSeeder
             throw new InvalidOperationException("Development seed service name is not configured.");
 
         await SeedMailpitChannelAsync(serviceName, cancellationToken);
+        await SeedServiceAsync(serviceName, cancellationToken);
 
         foreach (EmailTemplate template in CreateTemplates(serviceName))
         {
@@ -51,6 +55,18 @@ internal sealed class DevelopmentDataSeeder
         }
     }
 
+    private async Task SeedServiceAsync(string serviceName, CancellationToken ct)
+    {
+        var services = await _services.GetAllAsync(ct);
+        var service = services.SingleOrDefault(s => s.Name == serviceName);
+        if (service?.Languages.Any(l => l.Code == DefaultLanguageCode) == true)
+            return;
+        var isNew = service is null;
+        service ??= new NotificationServiceInfo { Name = serviceName };
+        service.Languages = [..service.Languages, new ServiceLanguageInfo { Code = DefaultLanguageCode }];
+        await _services.SaveAsync(service, isNew, ct);
+    }
+
     private async Task SeedMailpitChannelAsync(string serviceName, CancellationToken cancellationToken)
     {
         IReadOnlyList<EmailChannel> existingChannels = await _channels.GetByServiceAsync(