Feature: Add Angular basic example

Is your feature request related to a problem? Please describe.

There is no Angular example in the basic-server templates. Developers using Angular lack a reference implementation for building MCP Apps with the SDK, while other major frameworks (React, Vue, Svelte, Preact, Solid, Vanilla JS) all have starter templates.

Describe the solution you'd like

Add a basic-server-angular example that mirrors the existing basic-server templates, demonstrating:

• Angular standalone components with signals for state management
• provideZonelessChangeDetection() for modern, Zone.js-free change detection
• MCP App SDK integration (App class, connect(), callServerTool(), sendMessage(), sendLog(), openLink())
• Host theming support (applyDocumentTheme, applyHostStyleVariables, applyHostFonts)
• Vite + vite-plugin-singlefile build pipeline for single-file HTML output
• E2E test coverage with golden screenshot

Describe alternatives you've considered

N/A

Additional context

The example follows the same structure as the other basic-server templates: a get-time tool with a UI resource at ui://get-time/mcp-app.html, using Express for HTTP transport and stdio support. It uses Angular 21 with standalone components and signals — no NgModules or Zone.js required.

Start by comparing the existing basic-server templates and their E2E tests, especially the get-time tool, ui://get-time/mcp-app.html resource, and golden screenshot coverage. Add the Angular standalone, signals-based example with the specified MCP App SDK integrations, Express HTTP and stdio support, and single-file Vite build; done means the example builds and its E2E screenshot test passes.