Restructure train/: nest shards into chunk subdirs (batch 97/98)

Restructure train/: nest shards into chunk subdirs (batch 32/98)

Restructure train/: nest shards into chunk subdirs (batch 31/98)

Restructure train/: nest shards into chunk subdirs (batch 30/98)

Restructure train/: nest shards into chunk subdirs (batch 29/98)

Restructure train/: nest shards into chunk subdirs (batch 28/98)

Restructure train/: nest shards into chunk subdirs (batch 27/98)