example: langchain Agent (#38)

[AntiKnot]

What problem does this PR solve?

Issue Number: open #38

Problem Summary:

What changed and how does it work?

Add an Extraction Agent example, Extract information from text using TiDBVectorClient, LangChain, and LLM.

Check List

Tests

• [ ] Unit test
• [ ] Integration test
• [x] Manual test (add detailed scripts or steps below)
• [ ] No need to test

  • [ ] I checked and no code files have been changed.

Side effects

• [ ] Performance regression: Consumes more CPU
• [ ] Performance regression: Consumes more Memory
• [ ] Breaking backward compatibility

Documentation

• [ ] Affects user behaviors
• [ ] Contains syntax changes
• [ ] Contains variable changes
• [ ] Contains experimental features
• [ ] Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[sykp241095]

@AntiKnot Hello, AntiKnot, our colleague has just reached out to to thank you for great contribution~ You can check your mailbox for further connection as we want to send you some swag provided by TiDB Community.

[AntiKnot]

@sykp241095 Thx, project maintainers and official community.