### What problem does this PR solve?

1. The MySQL instance is configured with max_connections=1000,
but our connection pool was limited to max_connections: 100.
This mismatch caused connection pool exhaustion during performance
testing.

2.  Increase stale_timeout to resolve #6548

### Type of change

- [x] Performance Improvement

### What problem does this PR solve?

1.  Add delete_by_ids method
2. Add get_doc_ids_by_doc_names
3. Improve user_canvan_version's logic (avoid O(n) db IO)
4. Improve document delete logic (avoid O(n) db IO)

### Type of change

- [x] Performance Improvement

### What problem does this PR solve?

According to the
[[Rucongzhang](https://github.com/Rucongzhang)](https://github.com/infiniflow/ragflow/pull/7057#issuecomment-2827410047)
I added DB reconnection strategy in function `update_by_id`

### What problem does this PR solve?

Fixes #6548 

Add exception handling to prevent exceptions from propagating back to
the web, which may lead to failure in displaying conversation content.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

Co-authored-by: cm <caiming@sict.ac.cn>

Fix: Optimized the get_by_id method to resolve the issue of missing
exceptions and improve query performance

### What problem does this PR solve?

Optimized the get_by_id method to resolve the issue of missing
exceptions and improve query performance.
Optimization details:
1. The original method used a custom query method that required
concatenating SQL, which impacted performance.
2. The query method returned a list, which needed to be accessed by
index, posing a risk of index out-of-bounds errors.
3. The original method used except Exception to catch all errors, which
is not a best practice in Python programming and may lead to missing
exceptions. The get_or_none method accurately catches DoesNotExist
errors while allowing other errors to be raised normally.

### Type of change

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

### 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?

Fix errors detected by Ruff

### Type of change

- [x] Refactoring

### What problem does this PR solve?

Related source file is in Windows/DOS format, they are format to Unix
format.

### Type of change

- [x] Refactoring

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

* 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