Testing: Add Angular to automated visual regression testing

Pre-flight Checklist

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Problem or Motivation

The Angular demo currently has no automated visual regression coverage.

During the Angular 22 upgrade in #6521, the visual regression check for the Lucide migration had to be performed manually. The repository already contains Playwright-based screenshot tooling, but Angular is not integrated into it and the existing screenshots are not consistently compared against committed baselines in CI.

This issue should be started after #6521 has been merged.

🎤 Tell us your idea

Integrate the Angular demo into an automated visual regression testing environment.

The tests should:

• Render deterministic Angular UI states without depending on a live agent or external network requests.
• Cover at least running and completed tool calls, including their icons.
• Compare screenshots against committed reference images.
• Run automatically in CI when relevant Angular UI code changes.
• Build on or consolidate the existing Playwright screenshot tooling where practical.

Would you like to work on this?

• Yes, I’d love to work on it!
• I’m open to collaborating but need guidance.
• No, I’m just sharing the idea.