### What problem does this PR solve?

- Fix typo
- Remove unused import
- Format code

### Type of change

- [x] Other (please describe): typo and format

### What problem does this PR solve?

#2415

### Type of change

- [x] Performance Improvement

### What problem does this PR solve?

Fix return type annotation in truncate function

### Type of change

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

### What problem does this PR solve?

#1842 

### Type of change

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

### 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] Refactoring

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

### What problem does this PR solve?


### Type of change

- [x] Refactoring

### What problem does this PR solve?

### Type of change

- [x] Refactoring

### 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._

Issue link:#[[Link the issue
here](https://github.com/infiniflow/ragflow/issues/200)]

### Type of change

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

* clean rust version project

* clean rust version project

* build python version rag-flow

* add alot of api

* clean rust version project

* clean rust version project

* build python version rag-flow

* add llm API

* refine llm API

* add field progress msg into docinfo; add file processing procedure

* go through upload, create kb, add doc to kb