v0.10.2: fix v1.1 Zarr URL mapping

• Fix the Zarr store URL for 1.1, which remaps to 1.1-cam on source.coop until embeddings generation completes for the full store. This workaround lets 'v1.1' work until that happens! (#394 @maawoo @avsm)

• Improve the error message when Zarr store opening fails (#394 @maawoo @avsm)