* feat(themes): install counts, downloads, popularity & sort in the Theme Store
Each registry theme now carries an install count and a last-changed date. Store
rows show them in a dedicated meta panel (author, popularity bar, total
downloads, last changed), plus a sort dropdown (most popular / newest / name),
zebra-striped rows, a numbered pager, and a note that the stats refresh daily.
Adds a shared formatRelativeTime helper (formatLastSeen now delegates to it).
* test(themes): cover sort modes, pager jump and relative-time formatting
* fix(build): gate nvidia_quirk_active to Linux
Its only caller is the Linux branch of theme_animation_risk, so on Windows and
macOS the function was dead code and tripped clippy's -D warnings.
* docs: CHANGELOG + credits for theme store download stats & sort (#1036)
Psychotoxical