pub fn migrate_block_zones_v1(
wstore: &Arc<WaveStore>,
filestore: &Arc<FileStore>,
data_dir: &Path,
) -> MigrationStatsExpand description
One-shot migration of per-block agent session zones to per-agent
zones. Gated by a marker file under data_dir; running twice is a
no-op.
Failure mode: per-block errors are logged + counted; we do NOT abort startup. The marker file is written even on partial failure so we don’t retry indefinitely — operators can delete the marker to force a re-run.