docs(health): align shared-contract to shipped API + per-lib CLAUDE.md + cleanup

- Contract: DatabaseHealthCheck<TContext> ctor now shows IServiceProvider (resolves
  IDbContextFactory<TContext> when registered, else a scoped TContext; pool-safe)
- Contract: RequireActiveNode gains retryAfterSeconds = 5 default parameter
- Packages: remove dangling AspNetCore.HealthChecks.UI.Client PackageVersion (no
  csproj referenced it)
- Tests: fix CS8625 in RoleLessCases — use object?[] so null role rows compile
  warning-free under Nullable=enable
- Add ZB.MOM.WW.Health/CLAUDE.md (packages, responsibilities, consumer matrix,
  build/test/pack commands, status + pointer to components/health/)

ZB.MOM.WW.Health/Directory.Packages.props

@@ -11,7 +11,6 @@
 
     <!-- Health Checks / ASP.NET Core -->
     <PackageVersion Include="Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions" Version="10.0.7" />
-    <PackageVersion Include="AspNetCore.HealthChecks.UI.Client" Version="9.0.0" />
     <PackageVersion Include="Microsoft.AspNetCore.Mvc.Testing" Version="10.0.7" />
 
     <!-- gRPC -->