A group now has two lease lanes (migration 6600): `history` works the ranges the bounds hand out, `tail` the tail planner's, each with its own holder, window, snapshot and takeover redo, so a thread on the tail never wades through a group's history and a held group's tail isn't stuck behind it. The edge puts `--tail-threads` (EDGE_TAIL_THREADS, 1 of 2+ by default) of its threads on the tail lane; the group routes take `?lane=`. The lease order within a lane alternates the group with the most planned articles and the longest unheld one. The takeover redo puts back only the lane's ranges the window did after the snapshot, and a group whose last range is held by a holder gone quiet can be taken over. `coordinator:status` prints the catalog's room, the ranges by band, the last hour's rates, the held groups with their snapshots and the phase-2 backlogs. `tests/e2e` runs the real edge-node binary against the node API: the corpus-fill race, a failed stream and the restart that restores the snapshot, a restart without the snapshot file, a takeover (STREAM_CHUNK_WAIT_MINUTES is a setting now). CI builds the binary before the tests. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>