[FLINK-40146][connect/starrocks] Support AlterTableCommentEvent in StarRocks sink

[haruki-830]

Summary

This commit adds support for AlterTableCommentEvent to the Flink CDC pipeline StarRocks sink. When upstream table comments are changed, the StarRocks sink can now synchronize the table-level comment to StarRocks 3.1+ instead of treating the schema change as unsupported.

Key Changes

1. Support Table Comment Changes

• Added handling for AlterTableCommentEvent in StarRocksMetadataApplier.
• Applies table-level comment changes by executing ALTER TABLE ... COMMENT = "..." for supported StarRocks versions.
• Keeps the existing unsupported behavior for StarRocks versions lower than 3.1.

2. StarRocks Version Compatibility Check

• Added StarRocks version detection before applying table comment changes.
• Uses current_version() to get the StarRocks server version.
• Falls back to @@version_comment when current_version() is unavailable.
• Does not use version() because StarRocks documents it as a MySQL-compatible server version.

3. Table Comment Escaping

• Added escaping for table comment string literals used in the generated ALTER TABLE ... COMMENT SQL.
• Escapes backslashes, double quotes, newline characters, and carriage returns.

4. Documentation and Test Coverage

• Updated the StarRocks pipeline connector documentation in both English and Chinese.
• Added unit test coverage for table comment support, version compatibility, and comment escaping.
• Added integration test coverage for applying table comment changes.

JIRA Reference

https://issues.apache.org/jira/browse/FLINK-40146

Related Issue

https://issues.apache.org/jira/browse/FLINK-37203

[haruki-830]

@lvyanquan PTAL when you have time, thanks!