Solara thread formatting update

Upload Software/index.php and Software/assets/appearance.css to the matching
locations in your existing Solara installation, replacing those two files.
No database changes are required.

Removes visible Started and Last post labels while retaining both timestamps
in their original order: creation time, then latest post time. Hover and
accessibility labels identify each timestamp. Author, likes, replies and times
stay on one metadata line in Cards, Compact and Ultra Compact. Long author
names truncate when space is limited. Narrow screens retain responsive layouts.

Validated with PHP syntax check, existing thread activity tests and browser
layout fixtures at 1440, 1100, 768 and 390 pixels in all three views.
