AI converter progress UI stuck at 15% then jumps to 100% (no intermediate progress)

Source: Onboarding recap with Me Luzayisso (split from original recap).

Reported by: Danilo Schmidt — onboarding 2026-05-06 with Me Luzayisso (nl@etudeluzayisso.ch).

Issue: The AI converter progress stayed stuck at 15% for several minutes, then suddenly jumped to 100% without showing any intermediate progress.

Note: UX bug at minimum (progress reporting); may also indicate a backend stall hiding behind the static %.