What is the purpose of the change

This pull request adds Table API/SQL support for the BITMAP data type introduced in FLIP-556. It integrates BITMAP into Flink's type system, internal data format, planner, and code generation, enabling BITMAP columns to be used in SQL queries and Table API programs.

This is the third PR in the FLIP-556 series:

• PR 1 (FLINK-39183): Parser support
• PR 2 (FLINK-39184): DataStream API support (flink-core)
• PR 3 (FLINK-39185): Table API/SQL support (this PR)

Brief change log

Suggested review order:

1. LogicalType system: Added BitmapType, LogicalTypeRoot.BITMAP, LogicalTypeFamily.EXTENSION, visitor support, cast rules, and type parsing
2. DataType / API layer: Added DataTypes.BITMAP(), registered type mappings in ClassDataTypeConverter, TypeInfoDataTypeConverter, and ValueDataTypeConverter
3. Internal data format: Extended RowData/ArrayData with getBitmap(), implemented in BinaryRowData/BinaryArrayData/GenericRowData/GenericArrayData/NestedRowData; added BinarySegmentUtils.readBitmap() and BinaryWriter.writeBitmap()
4. Planner integration: Added BitmapRelDataType, integrated into FlinkTypeFactory (bidirectional conversion between BitmapType and BitmapRelDataType), extended CodeGenUtils for code generation, and updated ExpressionReducer
5. Cast rules: Added BitmapToStringCastRule and BitmapToBinaryCastRule (with trim/pad semantics); restricted CAST(x AS BITMAP) in SqlCastFunction
6. Data converters: Added BitmapBitmapConverter, DataFormatConverters.BitmapConverter, and JSON serialization/deserialization for BitmapType

Verifying this change

This change added tests and can be verified as follows:

• BitmapSemanticTest: End-to-end integration tests for BITMAP in SQL/Table API, covering source/sink roundtrip, projection, filtering, UDF invocation, and UDAF aggregation
• BinaryRowDataTest / BinaryArrayDataTest: Unit tests for BITMAP read/write in binary row and array formats
• RowDataTest: Verifies BITMAP field access and FieldGetter in RowData
• DataTypesTest: Verifies DataTypes.BITMAP() resolution and class mapping
• LogicalTypesTest: Tests BitmapType properties, serialization string, and cast compatibility
• ProjectionCodeGeneratorTest: Verifies BITMAP field projection in generated code
• TypeInferenceExtractorTest: Tests type inference for UDFs that accept/return BITMAP, including rejection of custom Bitmap implementations
• CastRulesTest: Tests cast rules

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): yes (RowData, ArrayData, DataTypes, BinaryWriter)
• The serializers: no
• The runtime per-record code paths (performance sensitive): yes (new getBitmap/writeBitmap code paths, but only activated for BITMAP type columns)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? yes
• If yes, how is the feature documented? not documented (documentation will be added when the full BITMAP type support is complete, including built-in functions)