Angular 21 migration topics

[droshev]

Angular 21 is out. With version 20 and 21 there are quite some improvements there. We need to analyze and decide what we should adopt and when. It doesn't mean we have to do everything in one shot.
Here are some topics to be considered:

• standalone API (moving away from NgModules)
• properly usage of signal(computed and linked) based input/output, change detection, completely zoneless
• control flow syntax (moving away from *ngIf/*ngFor to @if/@for
• dependancy injection like @inject
• Style Guide
• testing
• Angular Aria and its directives(includes keyboard interactions, ARIA attributes, focus management, RTL, and screen reader support)

Something to explore:

• MCP Server
• Animations
• Async reactivity with resources (explore resource API)
• Experimental Signal Forms
• performance measurements
• Routing

How to do the migration:

• in one shot - unrealistic
• gradually - when we touch a component we do the migration
• less gradually - do it only when it is needed
• never - hopefully not the case

Create a document or a Style Guide what to do and when so we can use it when we touch a component.

We need to plan and assign the topics