Refactor web search plugin and clean up code

Refactored the web search plugin by removing the old Bing search implementation and reorganizing the plugin structure. Introduced modular search engine classes under 'web_search_tool/engines' and utility tools under 'web_search_tool/tools' and 'web_search_tool/utils'. Updated references and initialization logic to support multiple search engines and improved maintainability. Also performed minor code cleanups and replaced 'except ...: pass' with 'except ...: ...' for brevity.

src/chat/memory_system/instant_memory.py

@@ -25,14 +25,6 @@ class MemoryItem:
         self.keywords: list[str] = keywords
         self.create_time: float = time.time()
         self.last_view_time: float = time.time()
-
-
-class MemoryManager:
-    def __init__(self):
-        # self.memory_items:list[MemoryItem] = []
-        pass
-
-
 class InstantMemory:
     def __init__(self, chat_id):
         self.chat_id = chat_id
@@ -219,14 +211,12 @@ class InstantMemory:
         try:
             dt = datetime.strptime(time_str, "%Y-%m-%d %H:%M:%S")
             return dt, dt + timedelta(hours=1)
-        except Exception:
-            pass
+        except Exception: ...
         # 具体日期
         try:
             dt = datetime.strptime(time_str, "%Y-%m-%d")
             return dt, dt + timedelta(days=1)
-        except Exception:
-            pass
+        except Exception: ...
         # 相对时间
         if time_str == "今天":
             start = now.replace(hour=0, minute=0, second=0, microsecond=0)