Feat: message manage (#12196)

### What problem does this PR solve?

Manage message and use in agent.

Issue #4213 

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

memory/utils/msg_util.py

@@ -0,0 +1,37 @@
+#
+#  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.
+#
+import json
+
+
+def get_json_result_from_llm_response(response_str: str) -> dict:
+    """
+    Parse the LLM response string to extract JSON content.
+    The function looks for the first and last curly braces to identify the JSON part.
+    If parsing fails, it returns an empty dictionary.
+
+    :param response_str: The response string from the LLM.
+    :return: A dictionary parsed from the JSON content in the response.
+    """
+    try:
+        clean_str = response_str.strip()
+        if clean_str.startswith('```json'):
+            clean_str = clean_str[7:]  # Remove the starting ```json
+        if clean_str.endswith('```'):
+            clean_str = clean_str[:-3]  # Remove the ending ```
+
+        return json.loads(clean_str.strip())
+    except (ValueError, json.JSONDecodeError):
+        return {}