Saves created per user action at exit should not be replaced by auto-saves created by a timer

[HebaruSan]

Summary

"Good" saves that were created as per user intention, and therefore have undergone a process of at least casual consideration as to the value of the current game state, can be auto-deleted when a new auto-save is created in response to a background timer.

Details

There are two kinds of saves: Auto and manual.

Auto-saves are (mostly) created in the background on a timer in a rotating bucket of 4; once the bucket is full, the oldest one is automatically deleted when the next auto-save is generated, which makes sense to save space and clutter. Auto-saves are generated unconditionally, and if the user loses a craft due to (say) the explode-on-docking bug, and the user does not wish for that state to be preserved, the only way to prevent a subsequent auto-save is to load immediately. Otherwise the auto-save bucket can gradually fill up with what the user would consider "useless" saves, and older "valid" ones are lost.

Manual saves are immune from this auto-deletion; they endure forever. This  makes sense because the user has specifically requested that game state to be preserved.

When you exit the game, it prompts you to save before exiting (I cannot capture a screenshot because I'm not in Windows at the moment). This raises a question: Is this a manual save or an auto save? The answer seems to be that these saves go into the auto-save bucket, which means that even though the user has specifically thought about it and requested that game state to be preserved, it can be lost later without the user requesting it.

Suggestions

Treat saves created when the user clicks "Save and Exit" as manually created saves, immune from auto-deletion.