feat: ZipStore accepts open binary file-like objects

[jhamman]

Summary

Allows constructing a ZipStore from any seekable binary reader, enabling zip archives on remote storage:

• io objects (BytesIO, fsspec file objects) are used directly
• minimal readers that are not io.IOBase instances and whose read() may return buffer-protocol objects rather than bytes (e.g. obstore.ReadableFile) are adapted via a small io.RawIOBase wrapper when opened for reading

clear()/move() raise NotImplementedError for file-object-backed stores.

For reviewers

This is the first of a series of Pull Requests toward #2943.

Author attestation

• I am a human, these are my changes, and I have reviewed and understood every change and can explain why each is correct.

TODO

• Add unit tests and/or doctests in docstrings
• Add docstrings and API docs for any new/modified user-facing classes and functions
• New/modified features documented in docs/user-guide/*.md
• Changes documented as a new file in changes/
• GitHub Actions have all passed
• Test coverage is 100% (Codecov passes)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.87%. Comparing base (eefa424) to head (b5f99fb).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4187      +/-   ##
==========================================
+ Coverage   93.84%   93.87%   +0.02%     
==========================================
  Files          91       91              
  Lines       12549    12594      +45     
==========================================
+ Hits        11777    11822      +45     
  Misses        772      772              

Files with missing lines	Coverage Δ
src/zarr/storage/_zip.py	98.18% <100.00%> (+0.46%)	⬆️

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