Prefer importlib.metadata over pkg_resources for version detection

[Copilot]

pkg_resources is deprecated and triggers UserWarning on newer setuptools. This updates version detection to use the modern importlib.metadata API first, falling back to pkg_resources for Python < 3.8.

Changes

pycoin/__init__.py:

• Try importlib.metadata first (Python 3.8+)
• Fallback to pkg_resources if unavailable
• Use specific exceptions (PackageNotFoundError, DistributionNotFound) instead of broad Exception catches

tests/version_test.py:

• Add test coverage for __version__ attribute validation

Before/After

# Before: pkg_resources first (deprecated)
try:
    from pkg_resources import get_distribution
    version = get_distribution(__name__).version
except ImportError:
    from importlib import metadata
    version = metadata.version("pycoin")

# After: importlib.metadata first (modern)
try:
    from importlib.metadata import version as get_version, PackageNotFoundError
    version = get_version("pycoin")
except ImportError:
    from pkg_resources import get_distribution, DistributionNotFound
    version = get_distribution("pycoin").version

Eliminates deprecation warnings while maintaining backward compatibility.

Original prompt

Summary

Update the version detection in pycoin/__init__.py to use importlib.metadata as the primary import path, with pkg_resources as a fallback for backward compatibility.

Context

The current implementation in pycoin/__init__.py prefers pkg_resources when available, even though:

1. pkg_resources is deprecated and scheduled for removal in setuptools
2. Using pkg_resources triggers a UserWarning on newer setuptools versions
3. importlib.metadata is the modern, recommended approach for version detection

Changes Required

Reverse the import order in pycoin/__init__.py to:

1. Try importlib.metadata first (modern approach)
2. Fall back to pkg_resources if available (backward compatibility)
3. Use "unknown" as a final fallback

This ensures forward compatibility and eliminates deprecation warnings while maintaining backward compatibility for environments that haven't updated setuptools yet.

Related Issue

Addresses issue #424: "When will pkg_resources be fully removed in favor of importlib.metadata?"

This pull request was created from Copilot chat.

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[richardkiss]

Looks good