Add data validation methods and StreamWriter performance improvements

[shady-910]

Add data validation functionality to excelize-py along with significant StreamWriter performance improvements and new features.

New Data Validation Support

• DataValidation class with helper methods for setting validation types
• DataValidationType enum (whole, decimal, list, date, time, textLength, custom)
• DataValidationOperator enum (between, equal, greaterThan, lessThan, etc.)
• DataValidationErrorStyle enum (stop, warning, information)
• add_data_validation() - apply validation rules to cell ranges
• get_data_validations() - retrieve all validations from a worksheet

StreamWriter Performance Optimizations

• set_rows() batch method - Write multiple rows in a single FFI call
• Direct ctypes assignment - Eliminated dataclass reflection overhead
• start_col parameter - Flexible column positioning for set_rows()
• set_col_style() method - Efficient bulk column styling during streaming

Cell Class for Styled Streaming

• New Cell dataclass with value, style_id, and formula fields
• Enables writing styled cells and formulas through StreamWriter
• Preserves header formatting when using streaming for large datasets

In-Memory Serialization

• File.write_to_buffer() - Serialize workbook to bytes without disk I/O

Test plan

• Test add_data_validation with all validation types
• Test get_data_validations retrieves existing validations
• Verify set_rows performance with large datasets (300K+ rows)
• Test Cell class preserves styles in StreamWriter
• Verify write_to_buffer matches save_as performance

[Copilot]

Pull request overview

This PR extends the excelize-py FFI surface to support Excel data validations and adds several StreamWriter features aimed at reducing Python↔Go call overhead (batch row writes, bulk column styling), plus a new in-memory serialization API.

Changes:

• Added DataValidation types/helpers and new add_data_validation() / get_data_validations() bindings.
• Added StreamWriter enhancements: set_rows() batch write, set_col_style() / set_col_styles() column styling, and Cell support for styled/formula streaming.
• Added File.write_to_buffer() for in-memory workbook serialization and bumped version to 0.0.9.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
types_py.py	Adds DataValidation enums/helpers and a Cell dataclass for styled streaming.
types_go.py	Extends ctypes structs for Interface (StyleID/Formula) and adds result structs for new APIs.
types_c.h	Extends C ABI structs for Interface, DataValidation, and bytes-return result.
main.go	Implements new exported FFI functions (data validation, streaming batch/style, write-to-buffer) and updated interface conversion.
excelize.py	Adds Python-facing APIs for new FFI functions plus performance-focused conversions for streaming.
test_excelize.py	Adds tests for new StreamWriter/data validation features and adjusts VBA project test path.
setup.py	Bumps package version to 0.0.9.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (645d2ef) to head (906568f).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   100.00%   100.00%            
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  Files            4         4            
  Lines         3713      3907   +194     
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+ Hits          3713      3907   +194     

Flag	Coverage Δ
unittests	100.00% <100.00%> (ø)

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[xuri]

Thanks for your contribution. I made some changes based on your branch.