feat: 优化存档管理和工具槽管理，改进数据类型转换，增强代码可读性

Assets/_Game/Scripts/Core/Save/GameSaveManager.cs

@@ -235,10 +235,10 @@ namespace BaseGames.Core.Save
                 return new SlotSummary
                 {
                     SlotIndex    = slotIndex,
-                    Playtime     = root["Meta"]?["Playtime"]?.Value<float>() ?? 0f,
-                    LastSaved    = root["Meta"]?["LastSaved"]?.Value<string>(),
-                    SceneName    = root["Player"]?["Scene"]?.Value<string>(),
-                    ActiveFormId = root["Player"]?["ActiveFormId"]?.Value<string>(),
+                    Playtime     = (float?)root["Meta"]?["Playtime"]  ?? 0f,
+                    LastSaved    = (string)root["Meta"]?["LastSaved"],
+                    SceneName    = (string)root["Player"]?["Scene"],
+                    ActiveFormId = (string)root["Player"]?["ActiveFormId"],
                 };
             }
             catch { return null; }