[parent] #1339
Problem
Fork replay duplicates entire history; fork path skips snapshot-boundary handshake (model.go ~5233).
Outcome
Use snapshot-boundary handshake on fork like session switch.
Acceptance criteria
- Fork renders history exactly once.
Test-first plan
Fork single-render regression test (expected red).
Impact analysis
TUI-only.
[parent] #1339
Problem
Fork replay duplicates entire history; fork path skips snapshot-boundary handshake (
model.go~5233).Outcome
Use snapshot-boundary handshake on fork like session switch.
Acceptance criteria
Test-first plan
Fork single-render regression test (expected red).
Impact analysis
TUI-only.