Test: Add tests for chunk API endpoints (#8616)

### What problem does this PR solve?

- Add comprehensive test suite for chunk operations including:
  - Test files for create, list, retrieve, update, and delete chunks
  - Authorization tests
  - Batch operations tests
- Update test configurations and common utilities
- Validate `important_kwd` and `question_kwd` fields are lists in
chunk_app.py
- Reorganize imports and clean up duplicate code

### Type of change

- [x] Add test cases

test/testcases/test_web_api/test_chunk_app/conftest.py

@@ -0,0 +1,49 @@
+#
+#  Copyright 2025 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+
+from time import sleep
+
+import pytest
+from common import batch_add_chunks, delete_chunks, list_chunks, list_documents, parse_documents
+from utils import wait_for
+
+
+@wait_for(30, 1, "Document parsing timeout")
+def condition(_auth, _kb_id):
+    res = list_documents(_auth, {"kb_id": _kb_id})
+    for doc in res["data"]["docs"]:
+        if doc["run"] != "3":
+            return False
+    return True
+
+
+@pytest.fixture(scope="function")
+def add_chunks_func(request, WebApiAuth, add_document):
+    def cleanup():
+        res = list_chunks(WebApiAuth, {"doc_id": document_id})
+        chunk_ids = [chunk["chunk_id"] for chunk in res["data"]["chunks"]]
+        delete_chunks(WebApiAuth, {"doc_id": document_id, "chunk_ids": chunk_ids})
+
+    request.addfinalizer(cleanup)
+
+    kb_id, document_id = add_document
+    parse_documents(WebApiAuth, {"doc_ids": [document_id], "run": "1"})
+    condition(WebApiAuth, kb_id)
+    chunk_ids = batch_add_chunks(WebApiAuth, document_id, 4)
+    # issues/6487
+    sleep(1)
+    return kb_id, document_id, chunk_ids