Replace npm/React client-side with Blazor Server in Samples.Tab

[Copilot]

Samples.Tab was triggering dependabot alerts for npm packages (React, Vite, TypeScript, Teams JS client SDK). Since this is a .NET repo, replace the entire client-side stack with Blazor Server to eliminate npm entirely.

Changes

• Removed Web/ folder (package.json, package-lock.json, vite config, tsconfig, React/TSX sources)
• Replaced embedded static file serving with Blazor Server interactive components
• Updated Program.cs to wire up AddRazorComponents().AddInteractiveServerComponents() and MapRazorComponents<App>()
• Simplified .csproj — removed GenerateEmbeddedFilesManifest, EmbeddedResource glob, and Microsoft.Extensions.FileProviders.Embedded package reference

The tab is still served at /tabs/test and the post-to-chat bot function remains unchanged.

// Program.cs - before
app.AddTab("test", "Web/bin");

// Program.cs - after
app.MapRazorComponents<App>()
    .AddInteractiveServerRenderMode();