Five test the constructor only (seed handling, eager profile build,
fail-fast pin validation) and always run. Four spin up the patched
Firefox and exercise the full `with InvisiblePlaywright(...)` lifecycle,
gated on a locally cached binary so CI without the binary skips
cleanly. All 230 tests pass on Windows with the binary fetched.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
