Workspace serialization additions

[JosephTLyons]

Check for existing issues

• Completed

Describe the feature

• Add a setting that restores all windows open from the previous Zed session #5058
• Zed window should remember last window size and position when opening single files #5258
• Preserve untitled files for next time #4985
• Persist undo history across restarts #4942
• Left sidebar doesn't remember its width #4910
• Remember unsaved changes #4683

If applicable, add mockups / screenshots to help present your vision of the feature

No response

[rkusa]

I was happy to see basic workspace restoration land in the latest version! IMHO, with the basic restoration in place, the following issues got more important to be able to get back to a clean slate:

• Command to recursively collapse all directories in project browser #5496
• Options for bulk closing tabs #5317

[JosephTLyons]

Version 0.68.x will introduce a few new tab-closing options:

• close all items
• close clean items (saved editors)

[JosephTLyons]

Going to close this meta issue, as the serialization tag tracks these requests nicely.