feat!: disable auto-cleanup by default

[wjones127]

BREAKING CHANGE: disables auto-cleanup by default.

Summary

Changes WriteParams default to disable auto-cleanup by default, addressing community feedback in issue #3854.

Changes Made

• WriteParams::default() now sets auto_cleanup: None instead of Some(AutoCleanupParams::default())
• Updated existing test - Modified auto_cleanup_old_versions test to explicitly enable auto-cleanup since it no longer works with default params
• Added new test - test_auto_cleanup_default_disabled() verifies the new default behavior
• Enhanced test infrastructure - Extended MockDatasetFixture to support auto-cleanup configuration

Breaking Change Context

Auto-cleanup was previously enabled by default (PR #3572), but community feedback indicated this was unexpected behavior:

• Users didn't expect write queries to be delayed by cleanup operations
• Users expected version history to be preserved indefinitely unless explicitly configured
• The change was seen as a breaking change that could delete data unexpectedly

Test Results

• ✅ All auto-cleanup tests pass
• ✅ All write tests pass
• ✅ All cleanup tests pass
• ✅ Code formatting verified

API Impact

• Rust: WriteParams::default() now has auto_cleanup: None
• Python: No changes needed - already defaults to auto_cleanup_options: None
• Existing datasets: Continue to work with their configured auto-cleanup settings

Users who want auto-cleanup can now explicitly opt-in by:

WriteParams {
    auto_cleanup: Some(AutoCleanupParams::default()),
    ..Default::default()
}

Fixes #3854

🤖 Generated with Claude Code

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.99%. Comparing base (5c98e47) to head (d04d8a0).
Report is 38 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4118      +/-   ##
==========================================
- Coverage   78.68%   77.99%   -0.70%     
==========================================
  Files         285      301      +16     
  Lines      113527   102889   -10638     
  Branches   113527   102889   -10638     
==========================================
- Hits        89328    80247    -9081     
+ Misses      20772    19685    -1087     
+ Partials     3427     2957     -470     

Flag	Coverage Δ
unittests	77.99% <100.00%> (-0.70%)	⬇️

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[github-actions]

Thank you for your contribution. This PR has been inactive for a while, so we're closing it to free up bandwidth. Feel free to reopen it if you still find it useful.