ci(react): Add basic catalog integration tests.

[ditman]

Description

This PR adds the remaining integration tests to the React adapter.

There are some minor changes to the react integration testing harness to improve the interaction with elements that require some more than a "click".

• Continues: ci(react): add browser-based integration testing to a2ui_explorer #1607
• Continues: fix(react): Small adjustments to some components. #1624

Pre-launch Checklist

• I signed the CLA.
• I read the Contributors Guide.
• I read the Style Guide.
• I have added updates to the CHANGELOG.
• I updated/added relevant documentation.
• My code changes (if any) have tests.
• If my branch is on fork, I have verified that scripts/e2e_test.sh passes.

If you need help, consider asking for advice on the discussion board.

[ditman]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces deep cloning of messages using structuredClone in App.tsx to prevent unintended mutations, refactors the test utility whenSettled to avoid nested act blocks, and adds a comprehensive suite of tests for various UI examples under tests/v0_9/. The review feedback highlights several opportunities to improve code safety in the new test files by replacing the non-null assertion operator (!) with optional chaining (?.) on lookup results that may fail.

[ditman]

OK, this should be ready for @josemontespg to take a look!

[josemontespg]

Amazing, thank you for adding integration tests for the react renderer!

[ditman]

I'll wait for the actions to finish, it's taking them a while to get scheduled again :/

Update: The new react tests have run and passed here: https://github.com/a2ui-project/a2ui/actions/runs/27647541272/job/81763115586?pr=1625#step:5:705