Install script now detects existing Node.js < 20 and upgrades it
instead of skipping. Supports apt, dnf, and apk package managers.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Quote all variable expansions in setup-bridge.sh, teardown-bridge.sh,
and install.sh. Fix redirect order and unused variable in test-suite.sh.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>