237 copy purge model storage functionality for main

[david-thrower]

Item 1: Bug fix:

When a Keras metric returns a non-float value like "inf", it would break casting to float / computing .min() / .max() for finding the best performing model.

Item 2:

• A model for each sub-trial are stored in the experiment folder Cerebros creates.
• In most cases only the best one from that meta-trial needs preserved.
• The models cached can hold up a lot of disk space, especially for NLP / CV problems.
• When running in a container [unless you have a mounted volume] these are stored in memory / in RAM, and the RAM pressure, therefore becomes cumulative.
• With the new feature, by default, this cache is not purged to maintain backward compatibility. When you explicitly set purge_model_storage_files=True when calling cerebros.simile_rabdom_search.SimpleRandomSearch().get_best_model(), the the storage will be purged after returning the best model.

Item 3:

Appended the 2 Ames CICD tests with a positive case and negative case test to endure this feature works when explicitly called and is not triggered unless called explicitly / proving backward compatibility.

[Thunderblok]

✅ What’s good

Fix for non-float metrics (e.g., "inf") avoids best-metric crashes.

New purge_model_storage_files=True option frees disk/RAM after picking best sub-trial model.

Tests include positive & negative cases to prove opt-in and back-compat.

⚠️ Small asks before merge

Metric safety

Coerce values via a helper that treats NaN/±inf as non-finite and falls back cleanly.

Add a tiny table test for ["1.0","inf","-inf","nan", None].

Purge safety

Guard against symlinks and .. paths; don’t follow links.

Wrap purge in try/except so failure doesn’t break get_best_model().

Log simple stats: {dirs_deleted, files_deleted, bytes_freed, duration_ms}.

DX/Docs

One line in README: “Use purge_model_storage_files=True to reclaim space (especially in containers).”

👍 Nice-to-have (don’t block)

Warn if artifacts are on Docker overlay (no volume mount).

Env toggle CEREBROS_PURGE_DEFAULT for ops environments.

✅ Verdict

Approve with the above nits. The change is backward-compatible, fixes a real footgun, and gives operators a clean way to control disk/RAM.