Graph drilling (LLM)
Liking a leaf topic asks a fast model (server-side) for
more-specific subtopics and grows the graph toward your niches.
Only likes count as interest. A card that was ≥60% visible for ≥500ms
then scrolled away unliked logs a skip — dwell time is never a positive
signal. Each card shows its fate in a status line once judged:
dimmed = seen & skipped, pink = liked. Unseen cards log nothing and
show no status. Each topic takes at most one skip per 30 min.