Add PolarsCursor for native Polars DataFrame support

This commit introduces PolarsCursor and AsyncPolarsCursor for native Polars
DataFrame support without requiring PyArrow as a mandatory dependency.

Key features:
- PolarsCursor: Synchronous cursor that returns results as Polars DataFrames
- AsyncPolarsCursor: Asynchronous cursor for non-blocking query execution
- Support for both regular queries and UNLOAD operations
- Proper type conversion for all Athena data types including decimal with precision/scale
- CSV reading via fsspec with S3 support
- Parquet reading via Polars native object_store

Implementation details:
- DefaultPolarsTypeConverter: Converts Athena types to Polars dtypes
- DefaultPolarsUnloadTypeConverter: Minimal converter for UNLOAD operations
- AthenaPolarsResultSet: Result set with Polars DataFrame conversion
- SQLAlchemy dialect support via AthenaPolarsDialect

Additional improvements:
- Added get_dtype method to base Converter class for extensible type handling
- Moved is_unload property to AthenaResultSet base class
- Updated pandas and arrow result sets to use get_dtype method
- Added as_polars() method to Arrow cursors for interoperability
- Comprehensive documentation and tests

Closes #436

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: laughingman7743

docs/api.rst

@@ -18,6 +18,7 @@ This section provides comprehensive API documentation for all PyAthena classes a
    api/sqlalchemy
    api/pandas
    api/arrow
+   api/polars
    api/s3fs
    api/spark
 
@@ -44,5 +45,6 @@ Specialized integrations
 - :ref:`api_sqlalchemy` - SQLAlchemy dialect implementations
 - :ref:`api_pandas` - pandas DataFrame integration
 - :ref:`api_arrow` - Apache Arrow columnar data integration
+- :ref:`api_polars` - Polars DataFrame integration (no pyarrow required)
 - :ref:`api_s3fs` - Lightweight S3FS-based cursor (no pandas/pyarrow required)
 - :ref:`api_spark` - Apache Spark integration for big data processing

docs/api/polars.rst

@@ -0,0 +1,40 @@
+.. _api_polars:
+
+Polars Integration
+==================
+
+This section covers Polars-specific cursors, result sets, and data converters.
+
+Polars Cursors
+--------------
+
+.. autoclass:: pyathena.polars.cursor.PolarsCursor
+   :members:
+   :inherited-members:
+
+.. autoclass:: pyathena.polars.async_cursor.AsyncPolarsCursor
+   :members:
+   :inherited-members:
+
+Polars Result Set
+-----------------
+
+.. autoclass:: pyathena.polars.result_set.AthenaPolarsResultSet
+   :members:
+   :inherited-members:
+
+Polars Data Converters
+----------------------
+
+.. autoclass:: pyathena.polars.converter.DefaultPolarsTypeConverter
+   :members:
+
+.. autoclass:: pyathena.polars.converter.DefaultPolarsUnloadTypeConverter
+   :members:
+
+Polars Utilities
+----------------
+
+.. autofunction:: pyathena.polars.util.to_column_info
+
+.. autofunction:: pyathena.polars.util.get_athena_type

docs/cursor.rst

@@ -319,6 +319,16 @@ AsyncArrowCursor
 
 See :ref:`async-arrow-cursor`.
 
+PolarsCursor
+------------
+
+See :ref:`polars-cursor`.
+
+AsyncPolarsCursor
+-----------------
+
+See :ref:`async-polars-cursor`.
+
 S3FSCursor
 ----------
 

docs/index.rst

@@ -20,6 +20,7 @@ Documentation
    sqlalchemy
    pandas
    arrow
+   polars
    s3fs
    spark
    testing

docs/introduction.rst

@@ -32,6 +32,8 @@ Extra packages:
 +---------------+---------------------------------------+------------------+
 | Arrow         | ``pip install PyAthena[Arrow]``       | >=7.0.0          |
 +---------------+---------------------------------------+------------------+
+| Polars        | ``pip install PyAthena[Polars]``      | >=1.0.0          |
++---------------+---------------------------------------+------------------+
 
 .. _features:
 
@@ -43,7 +45,7 @@ PyAthena provides comprehensive support for Amazon Athena's data types and featu
 **Core Features:**
   - **DB API 2.0 Compliance**: Full PEP 249 compatibility for database operations
   - **SQLAlchemy Integration**: Native dialect support with table reflection and ORM capabilities
-  - **Multiple Cursor Types**: Standard, Pandas, Arrow, S3FS, and Spark cursor implementations
+  - **Multiple Cursor Types**: Standard, Pandas, Arrow, Polars, S3FS and Spark cursor implementations
   - **Async Support**: Asynchronous query execution for non-blocking operations
 
 **Data Type Support:**