fix: check data batch nullability match with schema in write process

[lszskye]

Purpose

Linked issue: close #121

Verify whether the nullability of the data is consistent with that defined in the table schema during data writing.

Tests

WriteInteTest

[Copilot]

Pull request overview

This PR adds nullability validation to ensure data written to tables conforms to the schema's nullability constraints. The validation checks that fields marked as non-nullable in the schema do not contain null values in the data.

Changes:

• Implemented CheckNullabilityMatch utility function with support for nested types (struct, list, map)
• Added validation in the write process to verify data nullability matches schema constraints
• Enhanced API documentation to clarify nullability requirements

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/paimon/common/utils/arrow/arrow_utils.h	Added CheckNullabilityMatch method and supporting logic for validating nullability across nested data types
src/paimon/common/utils/arrow/arrow_utils_test.cpp	Added comprehensive test coverage for nullability validation across simple and complex nested types
src/paimon/core/operation/abstract_file_store_write.cpp	Integrated nullability check into the write process
test/inte/write_inte_test.cpp	Added integration test verifying nullability validation during write operations
test/inte/blob_table_inte_test.cpp	Removed obsolete blob-specific null value test
src/paimon/core/table/sink/commit_message_test.cpp	Simplified test schema and data generation to align with actual field types
include/paimon/record_batch.h	Enhanced documentation to clarify nullability requirements for RecordBatchBuilder
include/paimon/file_store_write.h	Enhanced documentation to clarify nullability requirements for Write method

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[zjw1111]

+1