Read services return soft-deleted rows #55

Files: core/csharp/MicroZen.Api/Services/OrganizationsService.cs:19-37, ClientsGrpcService.cs (reads)

What this is: GetOrganization, GetOrganizations, GetClient, GetManyClients.

Problem: None filter on DeletedOn == null. A disabled organization or deleted client is still returned by reads, so soft-delete has no effect on what callers see.

Fix: Add a DeletedOn == null condition, ideally as an EF Core global query filter on BaseEntity so every read is consistent.

If we skip it: "Deleted" records keep showing up.