feat(mediaserver): add item count retrieval for various media servers

app/modules/plex/__init__.py

@@ -253,6 +253,19 @@ class PlexModule(_ModuleBase, _MediaServerBase[Plex]):
             return server_obj.get_items(library_id, start_index, limit)
         return None
 
+    def mediaserver_items_count(self, server: str, library_id: Union[str, int]) -> Optional[int]:
+        """
+        获取指定媒体库可同步的媒体条目总数
+
+        :param server: 媒体服务器名称
+        :param library_id: 媒体库ID
+        :return: 媒体条目总数，查询失败时返回None
+        """
+        server_obj: Plex = self.get_instance(server)
+        if server_obj:
+            return server_obj.get_items_count(library_id)
+        return None
+
     def mediaserver_iteminfo(self, server: str, item_id: str) -> Optional[schemas.MediaServerItem]:
         """
         媒体库项目详情

app/modules/plex/plex.py

@@ -575,6 +575,22 @@ class Plex:
             user_state=user_state,
         )
 
+    def get_items_count(self, parent: Union[str, int]) -> Optional[int]:
+        """
+        获取指定媒体库可同步的媒体条目总数
+
+        :param parent: 媒体库ID
+        :return: 媒体条目总数，查询失败时返回None
+        """
+        if not parent or not self._plex:
+            return None
+        try:
+            section = self._plex.library.sectionByID(int(parent))
+            return int(section.totalSize) if section else None
+        except Exception as err:
+            logger.error(f"查询媒体库 {parent} 的媒体总数出错：{str(err)}")
+            return None
+
     def get_items(self, parent: Union[str, int], start_index: Optional[int] = 0, limit: Optional[int] = -1) \
             -> Generator[MediaServerItem | None, Any, None]:
         """