feat(artifacts): extend cache cleanup to allow specifying a target fraction

[moredatarequired]

Fixes

• Fixes WB-15212

Description

Add an optional target_fraction argument to ArtifactsCache.cleanup so that cleanup(target_fraction=0.25) will remove at least 75% of the current bytes and leave the most recently accessed 25% (or less) used.

🤖 Generated by Copilot at 8b5a1b8

Improved the cleanup function of the ArtifactsCache class to support custom cache size limits and ratios. Modified wandb/sdk/artifacts/artifacts_cache.py to implement the new functionality.

Testing

This is a dependency of #6149, which adds tests for full coverage at a higher level.

Checklist

• Include reference to internal ticket "Fixes WB-NNNNN" and/or GitHub issue "Fixes #NNNN" (if applicable)
• Ensure PR title compliance with the conventional commits standards

🤖 Generated by Copilot at 8b5a1b8

To reduce the cache size with ease
We added some optional keys
To the cleanup function
That controls the reduction
And calculates the target with these

[codecov]

Codecov Report

Merging #6152 (ce947ee) into main (cee7fdf) will decrease coverage by 0.13%.
The diff coverage is 66.66%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6152      +/-   ##
==========================================
- Coverage   77.96%   77.84%   -0.13%     
==========================================
  Files         377      377              
  Lines       43613    43627      +14     
==========================================
- Hits        34004    33960      -44     
- Misses       9557     9615      +58     
  Partials       52       52              

Flag	Coverage Δ
unittest	81.44% <66.66%> (-0.14%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
wandb/sdk/artifacts/artifacts_cache.py	90.40% <66.66%> (-3.30%)	⬇️

... and 17 files with indirect coverage changes

[szymon-piechowicz-wandb]

This breaks existing callsites, e.g.

wandb/wandb/cli/cli.py

Line 2208 in f0caa63

reclaimed_bytes = cache.cleanup(target_size, remove_temp)

New arguments can be safely added at the end, but not in the middle.

[moredatarequired]

🤦