### What problem does this PR solve?  
- The API documentation lacks detailed error code explanations. Added
error code tables to `python_api_reference.md` and
`http_api_reference.md` to clarify possible error codes and their
meanings.
- Error handling in the codebase is inconsistent. Standardized error
handling logic in `sdk/python/ragflow_sdk/modules/chunk.py`.
- Improved API comments by adding standardized docstrings to enhance
code readability and maintainability.

### Type of change  
- [x] Documentation Update  
- [x] Refactoring

### What problem does this PR solve?

Add license statement.

### Type of change

- [x] Refactoring

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

### What problem does this PR solve?

Close #3873

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

### What problem does this PR solve?

Manage ragflow-sdk with poetry
### Type of change

- [x] Refactoring

### What problem does this PR solve?

Turn resource to plural form

### Type of change
- [x] Refactoring

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

Fix some issues in API

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

### What problem does this PR solve?

Refactor Chunk API
#2846
### Type of change


- [x] Refactoring

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

### What problem does this PR solve?

#1102

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

### Type of change
#2485
- [x] Performance Improvement

### What problem does this PR solve?

#1102

### Type of change

- [x] Performance Improvement

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

### What problem does this PR solve?


### Type of change

- [x] Performance Improvement

### What problem does this PR solve?


### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

### What problem does this PR solve?

_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>