### What problem does this PR solve?
issue: https://github.com/infiniflow/ragflow/issues/2277
_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._
### Type of change
- [ ] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
### What problem does this PR solve?
feat: Do not display arrow icons on leaf node of folders #1826
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Add backend API support for moving files into other directory
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Let file in knowledgebases visible in file manager.
#162
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
