Add Zarr reader for CLI and library

[Dhanush010]

Description

Add a Zarr directory store reader for CLI and library use (Globus type list included; local browser upload intentionally not enabled yet, Zarr stores are directories; zip/UI upload is deferred).

Summary

• Add zarrReader with inventory(), read(), get_metadata(), and selected_keys for multi array stores (same selection model as HDF5)
• Register .zarr in READER_MAP for CLI/library; expose Zarr via GLOBUS_FILE_TYPES only (not the local upload dropdown)
• Add CLI/library/batch -selected keys / selected keys for HDF5 and Zarr path selection
• Add optional aidrin[zarr] dependency (zarr>=3.0.8,<3.2 on Python ≥3.11)
• Docs: CLI usage notes for Zarr and selected keys

Scope / limitations

• Directory path Zarr only (CLI, library, Globus listed but not the focus of this PR)
• Metrics expect tabular / compatible 1D arrays (or a single 2D array). Multi dim grids (ndim ≥ 3) are refused, no averaging/flattening inside AIDRIN, so metrics see raw values only
• Local web upload of .zarr is out of scope

What changes are proposed in this pull request?

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality not to work as expected; for instance, examples in this repository must be updated too)
• This change requires a documentation update

Checklist:

• My code modifies existing public API, or introduces new public API, and I updated or wrote documentation
• I have commented my code
• My code requires documentation updates, and I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes