Improve API Documentation, Standardize Error Handling, and Enhance Comments (#5990)

### 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

sdk/python/ragflow_sdk/modules/chunk.py

@@ -16,6 +16,12 @@
 
 from .base import Base
 
+class ChunkUpdateError(Exception):
+    def __init__(self, code=None, message=None, details=None):
+        self.code = code
+        self.message = message
+        self.details = details
+        super().__init__(message)
 
 class Chunk(Base):
     def __init__(self, rag, res_dict):
@@ -38,4 +44,8 @@ class Chunk(Base):
         res = self.put(f"/datasets/{self.dataset_id}/documents/{self.document_id}/chunks/{self.id}", update_message)
         res = res.json()
         if res.get("code") != 0:
-            raise Exception(res["message"])
+            raise ChunkUpdateError(
+                code=res.get("code"),
+                message=res.get("message"),
+                details=res.get("details")
+            )