fix(types): make RowKind short string parsing case-insensitive

[slfan1989]

Purpose

Linked issue: close #14

Make RowKind::FromShortString consistent with Java Paimon's RowKind.fromShortString behavior.

Java Paimon normalizes the input to uppercase before matching, so lowercase short strings such as +i, -u, +u, and -d are accepted. This PR updates paimon-cpp to accept the same lowercase variants.

Tests

Added unit test coverage for lowercase RowKind short strings:

• +i maps to INSERT
• -u maps to UPDATE_BEFORE
• +u maps to UPDATE_AFTER
• -d maps to DELETE

API and Format

No.
This change does not affect public API headers under include/, storage format, or protocol.

Documentation

No.
This is a compatibility bug fix and does not introduce a new feature.

Generative AI tooling

[slfan1989]

@zjw1111 @leaves12138 Could we accept this small change? Thank you very much!

[lxy-9602]

Thank you for the contribution. This fix looks correct and addresses the case-sensitivity issue.

We have a utility function, StringUtils::ToUpperCase, that has not been merged yet. Would it be possible to wait until that utility is available? I think it could make the code a bit cleaner. We expect to merge it soon, and then sync it in this PR if that works for you. Thanks!

[slfan1989]

Thank you for the contribution. This fix looks correct and addresses the case-sensitivity issue.

We have a utility function, StringUtils::ToUpperCase, that has not been merged yet. Would it be possible to wait until that utility is available? I think it could make the code a bit cleaner. We expect to merge it soon, and then sync it in this PR if that works for you. Thanks!

@lxy-9602 Thank you for the feedback. That sounds good to me.

I’m happy to wait until StringUtils::ToUpperCase is merged, and then I can update this PR to use the utility function to make the code cleaner.

Thanks again!