## Summary
- Skip actual Node.js downloads in E2E tests by returning a tiny test
URL instead of the real Node.js installer
- Skip opening external URLs in shell handler to avoid spawning browser
windows during E2E tests
- Both changes are conditional on `E2E_TEST_BUILD=true` environment
variable

## Test plan
- Run E2E tests with `E2E_TEST_BUILD=true` to verify external operations
are skipped
- Verify normal operation is unaffected when the environment variable is
not set

🤖 Generated with [Claude Code](https://claude.com/claude-code)
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---------
Co-authored-by: Will Chen <willchen90@gmail.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>