fix(ios-pwa): pad body for safe-area when masthead is hidden on mobile
Root cause (found via on-device debug): <=767px the masthead is display:none
(bottom-tab replaces it), so its safe-area padding has no effect (height 0) and the
profile-header lands at top=0 behind the Dynamic Island. Landscape (>767px) shows the
masthead so it worked there. Fix: pad body:not(.on-admin) by --ios-safe-top in the same
mobile media query, and make the JS adaptive (masthead hidden -> force body padding,
else masthead). Removed the temporary debug overlay; SW cache -> v14.