The committed placeholder's lane slot now takes the arriving card's
identity — .awaitingArrival keys as card:<id>, so when the echo reload
lands the ForEach sees one persisting element whose content swaps from
stub to card face instead of a removal and an insertion with two
scale+fade transitions (DESIGN/02 > overlays: the handoff must read as
one arrival). The awaiting face renders the card's exact chrome from
shared CardFaceMetrics, so any residual branch crossfade is between
pixel-identical renderings; the editing phase keeps its constant key so
typing identity holds. Slot position math is untouched.
CreateHandoffIdentityTests pins the key derivation.
Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY
rzen
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