REVERT: httpOnly cookie auth removed — reverts to JWT in localStorage.
The cookie implementation broke the login page (always-hidden auth screen).
localStorage token approach is restored fully:
- Login/register return token in JSON body
- getAuthHeaders() sends Authorization: Bearer header
- Session check reads localStorage token on load
- clearSession() removes localStorage token
Fix: slide preview padding — section elements now have 40px 48px padding
so text is not flush against the frame edges.
Kept from v3.14: AI panel context-aware options (word count, slide count,
quiz question toggle), delete confirmation wording per content type.
b5bfcc5489