Remove obsolete automatic optimiser

[georgeoshardo]

What changed

• Removed the obsolete automatic optimiser and its invalid notebook and renderer references.
• Removed optuna, cmaes, and their now-unused lockfile dependency closure.
• Kept SyMBac/metrics.py unchanged.

This removes an obsolete public module and avoids installing optimisation dependencies that the remaining package does not use.

Validation

• pixi install --locked
• pixi run --locked python -m pip check
• Built an isolated wheel, installed it into a temporary target, and imported SyMBac, SyMBac.renderer, and SyMBac.metrics.
• pixi run --locked python -m pytest tests/test_api_compat.py -q — 3 passed
• pixi run --locked python -m pytest -q — 63 passed

No file-absence test was added.

Merge note

This PR is based on current main and is independent of #64, which is being amended to retain optuna and cmaes. Before merging this deletion PR, rebase it onto main after #64 merges and rerun the validation above.