[Feature Request]Adding compatibility support for KingbaseES

Hi asyncpg maintainers,

  I am writing to propose adding support for KingbaseES, a widely used database in China that is highly compatible with the PostgreSQL wire protocol. I plan to contribute and maintain this adaptation over the next 2 months.

 To ensure the performance and stability of asyncpg remain unaffected, I will follow these principles:
 1.Non-Invasive Implementation: I will not modify the Cython-based protocol parser (asyncpg/protocol/). The changes will be isolated to Authentication tweaks and Type Introspection SQL adjustments (handling minor pg_catalog differences).
 2.Strict Testing: I will run the full asyncpg test suite against KingbaseES and add dedicated integration tests for any variant-specific edge cases.
 3.Maintenance Commitment: I fully understand the burden of supporting variants. I commit to taking long-term ownership of Kingbase-related issues to keep the driver up-to-date.

 I have already verified basic connections locally. Would the community be open to accepting a Pull Request for this? Also, do you prefer handling such variants via automatic detection (server version) or explicit connection flags?
 Thank you for your incredible work on this high-performance driver!

まず asyncpg/protocol/ と既存の Authentication および Type Introspection の SQL パスを確認し、KingbaseES に関連する PostgreSQL の前提を特定します。それらのパスを報告されている pg_catalog の差異と比較し、サーバーバージョンの検出と明示的な接続フラグのどちらが適切かを判断します。基本的な接続が機能し、バリアント固有の統合テストに合格し、完全な asyncpg テストスイートが KingbaseES に対して引き続き安定していれば完了です。