Fix transfer quantity, unify date format, align demo seeds

Stock Transfer list showed 0.00 (read in instead of out); stock-out/transfer forms show the location quantity; dates display as YYYY-MM-DD HH:mm:ss. Demo seeds map product accounts, use product names and supplier batches, and add demo_seed_assets.php.

app/setting/users.php

@@ -257,9 +257,7 @@
       const license_badge = license_html(u.license);
       const access_badge  = app_access_html(u.app_access);
 
-      const joined = u.created_at
-        ? new Date(u.created_at).toLocaleDateString('en-GB', {day:'2-digit', month:'short', year:'numeric'})
-        : '—';
+      const joined = u.created_at ? format_date(String(u.created_at).split(' ')[0]) : '—';
 
       const is_pending = u.status === 'pending' && u.is_pending_invite == 1;