[Fixes #73683910] Displaying file stats for various uploaded files on the entry form, when those files exist.
[Delivers #73678434] Authors can now upload JPEGs as well as PNGs as cover art. Cover art filenames are now retained (and displayed on the form).
[Delivers #73682874]
[Delivers #74092276]
[Delivers #74186716] Authors can now no longer sneak in more than 3 entries per year.
Various display tweaks and fixes.