Add unit tests for ErrorBoundary and StreamingErrorBoundary components

[kanweiwei]

The error boundary components (web/components/error/ErrorBoundary.tsx) have no tests.

What to do:

1. Read ErrorBoundary.tsx to understand the component API
2. Create web/components/error/__tests__/ErrorBoundary.test.tsx
3. Test cases to cover:
   • Renders children when no error
   • Shows fallback UI when child throws
   • Custom fallback prop is used
   • onError callback is called
   • Reset button clears the error state
   • StreamingErrorBoundary renders with retry button
4. Run: pnpm -C web run test -- --run components/error

Skills needed: React testing, Vitest + React Testing Library

Reference: See existing component tests at web/components/agent/__tests__/ConversationView.empty-state.test.tsx

Estimated time: 2-3 hours

[snakefood3232]

The ErrorBoundary components need unit tests to verify they properly catch errors and display fallbacks. I'd handle this by writing Vitest + React Testing Library tests covering all the listed cases, following the existing test patterns. I can have a PR up in a few hours—I regularly write production tests for React error boundaries in TypeScript projects.