v2.70.0 - Sort by creation date

Sort the notes list by when a note was first created, requested in #537. No new permissions; notes are stored exactly as before.

Added

• Sort by creation date. The sort menu in the notes list now has Newest created first and Oldest created first. They use each note's original creation time, so editing an old note never moves it, which suits journals and other chronological notes. Pinned notes still stay on top, and like the other non-default sorts the list is flat, without Today/Yesterday sections. The default is unchanged (newest edits first). Thanks to @PriscillaOvO for the request. (#537)

Limits

• The list rows still show the last-edited time, not the creation time.
• Notes imported from a folder keep the creation time Markleaf recorded for them, which is not necessarily the file's own creation date.