fix: tighten array metadata field validation

[barlowa124]

Summary

Four array metadata fields accepted JSON outside the spec contract. shape: [true] parsed as (1,) because bool subclasses int. Document shape fields now reject booleans through parse_shapelike(..., reject_bool=True), while stored chunks/chunk_shape fields keep the lenient default since old versions wrote true there and repair tests codify reading them. attributes: [] parsed as {}. parse_attributes now requires a dict with string keys, matching the check GroupMetadata already applies. dimension_names: "xy" parsed as ("x", "y") because a bare string is iterable. Strings and bytes are excluded before the element check. storage_transformers: {"name": ...} parsed as a tuple of keys. Mappings are excluded from the iterable check.

Refs #4453, fifth checklist item.

For reviewers

The parse_shapelike signature gains a keyword-only reject_bool flag, with the lenient default preserving the repair path for stored chunk sizes. Worth a second look: attributes: null still parses to {}, matching the group's handling of missing attributes.

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 94.70%. Comparing base (069fd20) to head (bbf6b2d).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4494   +/-   ##
=======================================
  Coverage   94.69%   94.70%           
=======================================
  Files          94       94           
  Lines       13606    13624   +18     
=======================================
+ Hits        12884    12902   +18     
  Misses        722      722           

Files with missing lines	Coverage Δ
src/zarr/core/common.py	92.47% <100.00%> (+0.12%)	⬆️
src/zarr/core/metadata/common.py	100.00% <100.00%> (ø)
src/zarr/core/metadata/v2.py	90.65% <100.00%> (ø)
src/zarr/core/metadata/v3.py	96.91% <100.00%> (ø)

... and 1 file with indirect coverage changes

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