refactor: decouple read/write responsibilities and introduce ColumnBinding

[bengbengbalabalabeng]

Note

Wait until the current version is released before moving forward.

Purpose of the pull request

Related: #1104

What's changed?

• Separate Converter into WriteConverter (write-specific) and ReadConverter (read-specific) while preserving backward compatibility
• Introduce ColumnBinding to support column-scoped converters in dynamic/no-bean scenarios
• Introduce hierarchical CellDataConverterRegistry supporting local-first delegation
• Eliminate the tight coupling between CSV export and CellDataType in write workflows
• Ensure template fill compatibility, supporting both native cell writes and multi-variable text interpolation

For more examples, please refer to: #1104

Checklist

• I have read the Contributor Guide.
• I have written the necessary doc or comment.
• I have added the necessary unit tests and all cases have passed.