Yavsc.Blogs.Tests will need a fixture too. Lifting the cross-cutting
plumbing (Kestrel + self-signed cert + address discovery + lazy init)
into a new Yavsc.Tests.Shared project lets the next fixture inherit
from it without copying 200+ lines of setup boilerplate, and keeps
the Org.Tests fixture focused on its IdentityServer + SMTP seed.
* New project src/Yavsc.Tests.Shared with WebHostFixture (abstract)
and TestAuthPolicyProvider (test auth bypass via X-Test-Role).
* WebServerFixture in Org.Tests now inherits from WebHostFixture;
BuildApp + ConfigurePipelineAsync hold only Org-specific work.
* Two shared package versions promoted to the root Directory.Packages.props.
* Tests still 30/30 green.
The partial class ClientController had two constructors declared
across ClientController.cs and ClientController.Collections.cs.
ASP.NET Core DI failed to pick one at request time with:
System.InvalidOperationException: Multiple constructors accepting
all given argument types have been found in type
'Yavsc.Controllers.ClientController'.
Move IHtmlLocalizer<ClientController> into the primary constructor
in ClientController.cs and drop the duplicate one in
ClientController.Collections.cs. The Collections partial now keeps
only its readonly field and action methods; the constructor and
field assignment are unified on the main file.
Also add the missing 'using Microsoft.AspNetCore.Mvc.Localization;'
to ClientController.cs so IHtmlLocalizer resolves.
