Plugs into run.Ports.Checkpointer (the executor's call site is a P2 follow-up;
this provides the seam + impls ahead of it):
- checkpoint.go: CheckpointStore seam + RunCheckpoint{Meta, Messages, Iteration,
ActivePhase} + RunCheckpointMeta (mirrors mort's agentexec types).
- handle.go: New(store, meta, throttle, now) -> run.Checkpointer. Save writes a
throttled snapshot; Complete/Fail delete it (a cleanly finished or terminally
failed run is NOT a recovery candidate; a shutdown-interrupted run never calls
them, so its checkpoint survives ListInterrupted at boot). nil store -> no-op.
- memory.go: NewMemory() default (with the honest caveat that in-memory does
not survive the restart it exists to recover from — a durable store is mort's).
Tests: save+complete clears the recovery candidate; throttle skips in-window
saves; nil-store is a clean no-op. Core imports ZERO from checkpoint.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
