Userpro – User Profiles With Social Login v5.1.15

Stability fix. Full detail in `changelog.txt`. - Stability: PHP warning "Attempt to read property 'post_name' on null" on archive pages, 404s, and any non-single-post context is now suppressed. `get_post()` returns null on these pages and the title filter was reading `$post->post_name` without a null guard. The warning appeared in the site header on any page where UserPro was active but no post was in context. (`functions/hooks-actions.php`)