test(security): AuthEndpoints integration tests via TestServer (F1)

7 tests exercise AddOtOpcUaAuth + MapOtOpcUaAuth end-to-end against an
in-memory ConfigDb + stub ILdapAuthService. Covers /auth/login (204/401/503),
/auth/ping (401/200), /auth/token (200+JWT shape), /auth/logout (204+clear-cookie).

Scope is the auth contract — not the fused Host bootstrap (cluster + role
gating belongs in the Task 58 multi-node harness). HostBuilder + TestServer
is used directly instead of WebApplicationFactory<Program> because the
test project has no Program entry point and Host needs Akka cluster up.

tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests/ZB.MOM.WW.OtOpcUa.Security.Tests.csproj

@@ -12,6 +12,7 @@
         <PackageReference Include="Shouldly"/>
         <PackageReference Include="Microsoft.NET.Test.Sdk"/>
         <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing"/>
+        <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory"/>
         <PackageReference Include="xunit.runner.visualstudio">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>