Checkpoint, don't snapshot every commit
Decision. Time travel is built on checkpoints — git tags cut at
meaningful moments with a human label and one-line summary, appended to
.checkpoints/manifest.json — not on every commit or deployment.
Why. Every-commit timelines are noise; nobody scrubs through 400 micro-states. A curated, narrated timeline is the changelog before the product exists, and it’s what reconciliation passes actually read. (Default granularity is still open — DEC-0003.)