Use vitest-browser-react in ChatView browser tests

- replace manual `createRoot` mounting with `render`/`unmount` from vitest-browser-react
- add `vitest-browser-react` to web devDependencies and lockfile
9abf967700Julius Marminge committed on 3/5/2026, 6:20:34 PM· committed by Julius Marmingeparentcc83094
3 files changedLine totals unavailable