Comparison extra fails to import VectorBT with Plotly 7 #144

Problem

The declared comparison extra cannot import VectorBT when installed with the visualization extra on supported Python 3.12-3.14.

Reproduction

At Backtest main 3fc7d74d9b0d582b89914ace0bfb74edb337327a, on Linux with Python 3.12:

uv sync --dev --locked --extra comparison --extra viz
uv run --no-sync python -c "import vectorbt"

The lock resolves VectorBT 1.0.0 and Plotly 7.0.0. Import raises Plotly InvalidPropertyPath: scattermapbox. The opt-in public cross-engine contract command fails all three VectorBT cases while the six Backtrader/Zipline cases pass:

ML4T_COMPARISON_INPROC=1 uv run --no-sync pytest -q --no-cov tests/contracts/test_cross_engine_contracts.py

Expected behavior and repair

The declared extra should install together and execute its native comparison contracts. Keep the shared comparison group on Plotly below 7 for Python below 3.15, and check that shared installation in the compatibility workflow. VectorBT 1.1.1 is not a compatible alternative for this group: its pandas requirement conflicts with the Pyfolio dependency. Isolated parity environments keep their own locks.

The repair passed all nine native contracts. Twelve Python/platform resolution contexts preserve every other resolved package version; the Python 3.15 graph is unchanged. The existing Python minimum remains 3.12.

AI assistance

Codex reproduced the install/import and native contract failures, produced the focused dependency and CI changes, and ran the recorded checks. No independent human review or new platform support claim is asserted.