In order to lose progress when writing articles, content should always be saved in the background.
Every post should have an autosaved shadow copy that is constantly saved alongside the currently manually saved version (if any)
Shadow copies are always removed when a user manually saves the post.
If an autosaved shadow copy is available and diverges from the currently persisted main post, a user has the option to restore the shadow copy and continue working with it.
Autosaved shadow copies are never publicly or otherwise viewable, unless they are restored and then manually saved.
There can only be one autosave per post, concurrent usage can overwrite any previously autosaved copies.
Change "draft" checkbox and "cancel/save" button to "Cancel", "Save as draft", "Publish" -> "Cancel" leaves the edit window, autosaving. "Save as draft" saves a post as a draft and removes any shadow copy. "Publish" saves and publishes (draft=false) post and also removes any shadow copy.
In order to lose progress when writing articles, content should always be saved in the background.