GeezerVison

Summary

Fixes two issues with gangof4_plot(response) when passing a precomputed Gang of Four response.

• The default Hz=False was incorrectly treated as a frequency override, causing the call to raise ValueError.
• Plotting options were passed as a positional dictionary instead of keyword arguments.

The fix preserves the existing plant/controller call path and keeps frequency overrides invalid for precomputed responses.

Tests

Added regression tests for:

• Plotting a precomputed response in the expected 2×2 layout.
• Forwarding plotting options such as dB=True.
• Accepting Hz=False while rejecting frequency overrides (omega, omega_limits, omega_num, and Hz=True).

Ruff passed. Additional CI checks are running in [fork PR #2](huxiaoyi-ovo#2).

AI assistance: ChatGPT (GPT-6) helped identify the issue, prepare the fix, and add regression tests.