When dragging suffix cards into position, the inferred sequence was
constantly recalculating based on the card's real-time position,
causing suffix detection to flicker on/off. This created instability
when trying to place suffix cards.
Solution:
- Store stable positions for locked (prefix/suffix) cards in a ref
- Use stable positions instead of live positions for inference
- Clean up ref when cards are no longer locked
- Add useMemo import for stable card states computation
This ensures that once a card is locked in correct position, its
position in the inferred sequence remains stable even when other
cards are being dragged nearby.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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