Fix: Add Knowledge Base Document Parsing Status Check (#5966)

When creating and updating chats, add a check for the parsing status of
knowledge base documents. Ensure that all documents have been parsed
before allowing chat creation to improve user experience and system
stability.

**Main Changes:**

- Add document parsing status check logic in `chat.py`.
- Implement the `is_parsed_done` method in `knowledgebase_service.py`.
- Prevent chat creation when documents are being parsed or parsing has
failed.

### What problem does this PR solve?

fix this bug：https://github.com/infiniflow/ragflow/issues/5960

### Type of change

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

Co-authored-by: wenju.li <wenju.li@deepctr.cn>

api/apps/sdk/chat.py

@@ -40,6 +40,12 @@ def create(tenant_id):
         kb = kbs[0]
         if kb.chunk_num == 0:
             return get_error_data_result(f"The dataset {kb_id} doesn't own parsed file")
+        
+        # Check if all documents in the knowledge base have been parsed
+        is_done, error_msg = KnowledgebaseService.is_parsed_done(kb_id)
+        if not is_done:
+            return get_error_data_result(error_msg)
+    
     kbs = KnowledgebaseService.get_by_ids(ids) if ids else []
     embd_ids = [TenantLLMService.split_model_name_and_factory(kb.embd_id)[0] for kb in kbs]  # remove vendor suffix for comparison
     embd_count = list(set(embd_ids))
@@ -176,6 +182,12 @@ def update(tenant_id, chat_id):
                 kb = kbs[0]
                 if kb.chunk_num == 0:
                     return get_error_data_result(f"The dataset {kb_id} doesn't own parsed file")
+                
+                # Check if all documents in the knowledge base have been parsed
+                is_done, error_msg = KnowledgebaseService.is_parsed_done(kb_id)
+                if not is_done:
+                    return get_error_data_result(error_msg)
+                
             kbs = KnowledgebaseService.get_by_ids(ids)
             embd_ids = [TenantLLMService.split_model_name_and_factory(kb.embd_id)[0] for kb in kbs]  # remove vendor suffix for comparison
             embd_count = list(set(embd_ids))