PESYJE - Dynamic remaining-photo count + pointer cursor + higher-quality cover

Changes:
1. The last gallery tile no longer shows a fake fixed total.
   - If every photo fits: no count tile is shown.
   - If 1 photo is hidden: shows "1 Foto".
   - If 5 photos are hidden: shows "5 Foto".
   - Recalculates automatically when the viewport changes, including mobile.
2. Thumbnail arrows page through the hidden photos and recalculate the remaining count.
3. Photo hover uses the normal hand/pointer cursor, not zoom-in/plus.
4. New/reselected custom covers are generated at 2560x800, JPEG quality 94 for a sharper hero image.

IMPORTANT: an already-saved old 1600x500 cover cannot regain detail that was previously discarded. After this patch, re-upload the cover or choose it again from Gallery once to regenerate it at the new quality.

After Extract + Overwrite:
cd ~/pesyje
php artisan optimize:clear
