Remove unused imports across multiple modules

Cleaned up various files by removing unused or redundant import statements to improve code readability and reduce potential confusion. No functional changes were made.

src/chat/utils/chat_message_builder.py

@@ -256,7 +256,6 @@ def get_actions_by_timestamp_with_chat(
 ) -> List[Dict[str, Any]]:
     """获取在特定聊天从指定时间戳到指定时间戳的动作记录，按时间升序排序，返回动作记录列表"""
     from src.common.logger import get_logger
-    from src.common.database.sqlalchemy_database_api import get_db_session
     
     logger = get_logger("chat_message_builder")
     
@@ -349,7 +348,6 @@ def get_actions_by_timestamp_with_chat_inclusive(
     chat_id: str, timestamp_start: float, timestamp_end: float, limit: int = 0, limit_mode: str = "latest"
 ) -> List[Dict[str, Any]]:
     """获取在特定聊天从指定时间戳到指定时间戳的动作记录（包含边界），按时间升序排序，返回动作记录列表"""
-    from src.common.database.sqlalchemy_database_api import get_db_session
     with get_db_session() as session:
         if limit > 0:
             if limit_mode == "latest":
@@ -780,7 +778,6 @@ def build_pic_mapping_info(pic_id_mapping: Dict[str, str]) -> str:
     sorted_items = sorted(pic_id_mapping.items(), key=lambda x: int(x[1].replace("图片", "")))
 
 
-    from src.common.database.sqlalchemy_database_api import get_db_session
     for pic_id, display_name in sorted_items:
         # 从数据库中获取图片描述
         description = "内容正在阅读，请稍等"