Polars 1.12.0

⚠️ Deprecations

• Make some parameters of dt.add_business_days keyword-only (#19428)

🚀 Performance improvements

• Address inadvertent quadratic behaviour in expand_columns (#19469)
• Move rolling_corr/cov to an actual implementation on Series (#19466)
• Don't split par if cast to categorical (#19462)

✨ Enhancements

• Implement nested Parquet writing for High-Precision Decimals (#19476)
• Improve read_database typing (#19444)
• Respect include_index for pandas series (#19453)
• Add credential_provider argument to more read functions (#19421)
• Add IPC sink in new streaming engine (#19431)
• Support querying specific snapshot by id in scan_iceberg (#19388)

🐞 Bug fixes

• Include Array in to_physical (#19474)
• Don't panic in SQL temporal string check; raise suitable ColumnNotFound error (#19473)
• Properly raise on mean_horizontal with wrong dtypes (#19472)
• Make output dtype known for list.to_struct when fields are passed (#19439)
• Address inadvertent quadratic behaviour in expand_columns (#19469)
• Ensure sorted flag is unset after Int->String cast (#19470)
• Fix row_index of batched reader (#19465)
• Fix perfect groupby (#19461)
• Correct wildcard expansion for functions (#19449)
• Ensure struct eq/ne_missing also compares outer validity (#19443)
• Fix incorrect reverse on struct containing NULLs (#19446)
• Faulty escape_regex example (#19440)
• Capture groups should be ignored in replace when literal=True (#19413)
• Fix ColumnNotFound when using pl.element() inside list.eval (#19438)
• Updates error message in csv parser to recommend schema_overrides instead of deprecated dtypes argument (#19416)
• Incorrect .join(..., how="left").head(N) if N <= left_df.height() and there are duplicate matches (#19422)
• Support Array type in more DataType methods (#19427)
• Bug in group_tuples_perfect, tail was not processed properly (#19417)
• Ensure that ASCII* table formats do not use the UTF8 ellipsis char when truncating rows/cols/values (#19404)

📖 Documentation

• Fix docstrings for ATAN2 and ATAN2D SQL functions (#19351)

🛠️ Other improvements

• Undo conflicting fix (#19463)
• Simplify rust side of datetime (#19459)
• Add tests for data mismatch on read_json (#19425)
• Remove code in examples folder in favor of the user guide (#19430)

Thank you to all our contributors for making this release possible! @alexander-beedie, @cmdlineluser, @coastalwhite, @corleyma, @corwinjoy, @dvillaveces, @eitsupi, @gab23r, @janscholten, @nameexhaustion, @orlp, @ritchie46, @siddharth-vi, @stinodego and @wakabame