### What problem does this PR solve?


### Type of change

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

### What problem does this PR solve?

1. Validate the Python version should >= 3.11
2. Download nltk data

### Type of change

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

---------

Signed-off-by: jinhai <haijin.chn@gmail.com>
Co-authored-by: jinhai <haijin.chn@gmail.com>
Co-authored-by: Zhichang Yu <yuzhichang@gmail.com>

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

### What problem does this PR solve?

#1880
### Type of change

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

### What problem does this PR solve?

#1594
### Type of change

- [x] Refactoring

### What problem does this PR solve?



### Type of change

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

### What problem does this PR solve?

#1594

### Type of change

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

### What problem does this PR solve?

fix file preview in file management

### Type of change

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

* add front end code

* change licence

* rename web_server to API

* change name to web_server

* clean rust version project

* clean rust version project

* build python version rag-flow