StudyDesk v1.4.0

AI Study Debrief — post-session analysis via Gemini 2.5 Flash.

Optional "What did you cover?" field in the Save Session sheet. Extracts subject covered, comprehension score (1–5), confusion flags, and a one-line summary. Session list shows an AI pill + summary. Stats card shows avg comprehension over last 7 days and recurring confusion tags. Auth-gated — hidden when signed out.