v1→v2 Migration
Domain: Sessions & Persistence
Motivation
dsh-session-format-v1-to-v2 is a cardinality-changing migration: it consumes top-level assistant/chunk events and embeds their exact timed stream into the matching assistant/message. It records an assistant/attempt when a failed, retried, cancelled, or stream-error attempt reached settlement without a surface message. The edge densely remaps surviving events and every same-session sequence reference.
Concrete Example
After the migration the v2 codec stores one event per row and derives the inherited cut from a tagged session/end-seed marker.
Analogy
A re-encode that stitches fragmented clips into single complete takes.