[FLINK-37502][docs] Translate documentation for Disaggregated State Management into Chinese

[arvindKandpal-ksolves]

What is the purpose of the change

This pull request translates the documentation for Disaggregated State Management into Chinese,
including Chinese translations for State API V2, ForSt State Backend, and Disaggregated State pages.

Brief change log

• Chinese translation for State API V2 documentation
• Chinese translation for ForSt State Backend section in state_backends.md
• Chinese translation for Disaggregated State Management documentation
• Minor English doc fixes (typo fix in state_v2.md, grammar fix in state.md, heading level fix in state_backends.md)

Verifying this change

This change is a docs-only translation with no test coverage required.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

Was generative AI tooling

• Yes (please specify the tool below)

Generated-with: Claude Code

[arvindKandpal-ksolves]

Hi @Zakelly @davidradl, I have opened this PR to address the translation work from the closed PR #26312. All your previous review comments have been incorporated. Could you please take a look when you get a chance? Thank you!

[flinkbot]

CI report:

• d1c7222 Azure: SUCCESS

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[raminqaf]

Thanks for the contribution. Ideally, we the docs are translated by a native speaking person. We cannot really know if the translation of AI is good enough.

[arvindKandpal-ksolves]

Hi @raminqaf, thank you for the feedback. I completely understand the concern about translation quality. I want to clarify that while AI tooling was used as a starting point, the translation was carefully reviewed and all reviewer comments from the original PR #26312 by @Zakelly were incorporated. I am open to any corrections from native Chinese speakers in the community. If anyone would like to review and suggest improvements to the translation quality, I would be happy to update accordingly. I have put significant effort into this contribution and want to make sure it meets the community standards. Thank you for taking the time to look at this PR.