Polars 1.43.2：弃用 Categorical 转整数

⚠️ Deprecations

• Deprecate casts from Categorical to integer dtypes (#28525)
• Deprecate not setting the plan_stage argument in show_graph() (#28391)

🚀 Performance improvements

• Pushdown len() to concat/union inputs (#28570)

✨ Enhancements

• Issue FutureWarning on using from_arrow of ArrowStreamExportable (#28442)
• Add infer_schema_files parameter to scan_csv (#28440)

🐞 Bug fixes

• Properly propagate enum metadata for iceberg column mapping (#28580)
• Correctly write parquet field IDs for enums and categoricals (#28581)
• Fix arrow C interop binview offset (#28623)
• Fix duplicate hive values in hive pre-partition rewrite (#28621)
• Double-counted offset for Arrow export of sliced Series(Array) (#28602)
• Struct/List/Array equality handling in sort and join (#28601)
• More careful slice pushdown into joins (#28578)
• Preserve ordering in sliced unions (#28576)
• Drop input sortedness when casting to a string (#28574)
• Clear sortedness flags in StringChunked substring kernels (#28573)
• Bad mask handling when reading optional parquet column (#28547)
• Any operation on Unknown(Int) and Unknown(Float) should result in Unknown(Float) (#28545)
• Flip nulls_last after Expr.reverse() (#28572)
• Fix high blocking thread use in sink_parquet with async local path (#28543)
• Serialize LazyFrames backed by bytes (#28568)
• Release GIL in SQLContext.execute() (#28549)
• Propagate nulls_last in function_expr_sortedness (#28544)
• Incorrect slicing when a join requires sorting (#28541)

🛠️ Other improvements

• Fix duckdb delta extension install collision (#28607)

Thank you to all our contributors for making this release possible!

@BitWeaverDev, @Matt711, @Samoilov2004, @borchero, @dancsi, @dsprenkels, @kdn36, @masumi-ryugo, @nameexhaustion and @ritchie46