Add Identity Lab Blazor app with in-memory UltimateAuth playground and UI

[mckaragoz]

Motivation

• Introduce an interactive, isolated playground to demonstrate UltimateAuth features (authentication flows, user creation, device/session chains and authorization) via a Blazor UI.
• Provide a living reference for client integration and public API coverage through a small demo app that uses the in-memory UltimateAuth bundle.

Description

• Added a new Blazor app at apps/identity-lab/CodeBeam.UltimateAuth.IdentityLab and registered it in UltimateAuth.slnx under /Apps/ with a new CodeBeam.UltimateAuth.IdentityLab.csproj that references MudBlazor and the in-memory and Blazor client projects.
• Implemented app entry and hosting in Program.cs with server and client Blazor integration, in-memory UltimateAuth wiring, sample seed, routes, endpoints and antiforgery setup.
• Added UI components and pages: App.razor, Routes.razor, MainLayout.razor, pages Landing.razor, Access.razor (login/create account), Dashboard.razor (device chains, auth state, quick actions) and NotAuthorized.razor, plus _Imports.razor and CSS at wwwroot/app.css.
• Added a capability audit document CAPABILITY-AUDIT.md describing which UltimateAuth public APIs are exercised by the Identity Lab.

Testing

• No automated tests were added or executed as part of this change.

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Codex Task