Resolve Zarr config annotations from their nominal owner

[trissim]

Summary

• bind ZarrConfig once at the PolyStore module boundary
• remove method-local imports that made the quoted type annotation unresolved
• add a regression proving runtime type reflection resolves the authoritative config class

Verification

• 31 passed, 13 skipped in the Zarr and OME-Zarr focused suites
• focused Ruff undefined/import checks passed
• wheel and sdist built successfully
• twine check passed

[Copilot]

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[augmentcode]

^{PR Risk Analyzer Agent🛡️}

Risk Analysis 🛡️ · Low Risk

✅ Approved — Low-Risk Change

Details

• Hoists from .config import ZarrConfig to module scope and drops two redundant method-local imports. config.py imports only the external metaclass_registry package and stdlib and never imports polystore.zarr, so no import cycle is reintroduced.
• No runtime behavior change: the edit only makes the quoted 'ZarrConfig' annotation resolvable at runtime and bumps the package version 0.1.25 → 0.1.26.
• The test change only adds a get_type_hints regression test; no existing test is modified or weakened.

[augmentcode]

^{Deep Code Review Agent🐛}

Review completed with 1 suggestions.

[augmentcode]

Changing the project metadata to 0.1.26 leaves polystore.__version__ at 0.1.25, and this repository's release helper updates both files together. Published/install smoke checks can therefore report the previous package version even though the wheel metadata says 0.1.26.

Severity: low

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