refactor(library): extract premod action to controller
- Add PremodController at /library/premod
- Approve single article via ?approve={id} with POST-Redirect-GET and flash message
- Approve all via ?approve-all with POST-Redirect-GET and flash message
- Show empty state message when no articles pending moderation
- Show moderation button with counter on library main page for admins
- Fix section counters to exclude unmoderated articles (premod = 1 only)
- Update moderation links in Counters.php and notifications module
- Remove premod from array_includes in index.php
- Approve single article via ?approve={id} with POST-Redirect-GET and flash message
- Approve all via ?approve-all with POST-Redirect-GET and flash message
- Show empty state message when no articles pending moderation
- Show moderation button with counter on library main page for admins
- Fix section counters to exclude unmoderated articles (premod = 1 only)
- Update moderation links in Counters.php and notifications module
- Remove premod from array_includes in index.php