dog/git pack-log format work: index-emit (PIDX), the pack writer, and delta encoding. The store is *offset-only* — OFS_DELTA against an earlier object in the SAME pack, never REF_DELTA; a cross-pack base is stored RAW and reclaimed at GIT-006 recompaction (PackLog). Read side / LSM index shape live in Indices; keeper-side pool/wire in KEEP. Fix-and-land via Issues.
PIDXScan from_off tail scan: C core + dog/test/PIDX.c
tail case LANDED 8df1e213/b141ab81; open — the JABC binding half (_pack_scan still hardcodes 0, no pk.scan(out, fromOff), no JS test), so JS-099's reindex-on-open cannot start mid-pack from JS yet.
jab post
(fold-commit.writePack) feeds RAW today, so JS packs are non-native/bloated. Follow-up to PACK-001; distinct from the REF_DELTA path JS-037.