fix(lint): E501 on main — wrap 103-char test signature from #184

Description

The pitch.

`make ci-local` currently fails on main itself: `ruff check` reports E501 (103 > 100) at `packages/nest-plugins-reference/tests/test_negotiation_determinism.py:88`, introduced in #184. Every open hackathon branch rebased onto main inherits the red gate.

One-line wrap of the test signature, identical to `ruff format` output.

Verified: `ruff check` clean, `ruff format --check` clean, `pytest packages/nest-plugins-reference/tests/test_negotiation_determinism.py` 8/8 pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)