Polars 1.43.1

🚀 Performance improvements

• Optimize not(bool_f) to not_bool_f (#28474)

✨ Enhancements

• Allow callback sinks on cloud (#28458)

🐞 Bug fixes

• Fix panic on self join of scan_delta / scan_iceberg (#28468)
• Fix UB on first/last_non_null with empty chunk (#28495)
• Do not CSE non-column height expr on streaming engine (#28480)
• Propagate adjusted sortedness through Gather (#28493)
• Deduplicate the expression equality checks (#28483)
• Address 3VL issue with SQL NOT IN interaction with NULL values and joins (#28484)
• Use total comparison in Expr literal values (#28482)
• Ensure SQL SUM and CORR aggregates return NULL for all-null inputs, add TOTAL (#28475)
• Share null_count_dtype helper between Delta and Iceberg, fixing SchemaError (#28479)
• Remove non-output columns from the equi-join and semi/anti-join operators (#28446)
• Fix dropped slice on multiple unions (#28477)
• Fix in-memory engine incorrect slice on maintain order join (#28478)
• Check join schema by position (#28455)
• Block predicate pushdown past overwritten window keys (#28429)

📖 Documentation

• Update and restructure README (#28490)
• Minor fixes to Spark migration guide (#27730)
• Relocate Polars Cloud & On-Prem User Guide (#28462)
• Add notes on k8s operator (#28445)

🛠️ Other improvements

• Make hive_part extraction a function and public (#28507)
• Deduplicate the expression equality checks (#28483)
• Bump ruff and mypy package versions (#28456)
• Fix flaky test (#28454)

Thank you to all our contributors for making this release possible! @AnirudhRahul, @EndPositive, @Jesse-Bakker, @alexander-beedie, @carnarez, @dancsi, @mdroogh, @mroeschke, @nameexhaustion, @nchammas, @orlp, @r-brink and @ritchie46