[Natim]

Summary

Fixes #3731.

Removes all runtime use of pkg_resources from Pyramid and replaces it with importlib.resources. This drops the setuptools < 82 runtime pin and lets Pyramid work with modern setuptools releases where pkg_resources is deprecated or unavailable.

Asset overrides no longer hook into setuptools' global loader adapter (OverrideProvider / register_loader_type). Instead, Pyramid's own asset APIs look up IPackageOverrides from the application registry explicitly.

What changed

Resource access

• Added pyramid.path.ref_filename() and pyramid.path.resource_filename() as helpers for filesystem access to package resources (including extraction from zipped distributions via importlib.resources.as_file()).
• Rewrote PkgResourcesAssetDescriptor and PackageAssetSource to use importlib.resources.files().
• Updated package_path(), static_view, and abspath_from_asset_spec() to go through the new resolution path.

Asset overrides

• Removed OverrideProvider, pkg_resources.register_loader_type(), and the package.__loader__ = self hack in PackageOverrides.
• AssetResolver.resolve() now queries IPackageOverrides from the registry and passes overrides into PkgResourcesAssetDescriptor.
• static_view uses AssetResolver so overrides still work for static file serving.

Module layout

• Moved Resolver, AssetResolver, and DottedNameResolver to the new pyramid.resolver module.
• Re-exported from pyramid.path for backward compatibility.

Dependencies

• Removed setuptools from runtime dependencies in pyproject.toml.

Backward incompatibilities

• Asset overrides are no longer transparent to pkg_resources callers. Code that calls pkg_resources.resource_filename() (or related APIs) directly will not see overrides registered via config.override_asset(). Overrides apply only through Pyramid's asset APIs (AssetResolver, static_view, abspath_from_asset_spec, etc.).
• IPackageOverrides no longer extends IPEP302Loader. The PEP 302 loader passthrough methods on PackageOverrides have been removed.
• PackageOverrides no longer mutates package.__loader__.

Test plan

• Full test suite passes locally (2618 tests)
• Verified with setuptools>=82 installed (tested with 83.0.0)
• Added tests/test_resolver.py and tests/pkgs/assets/ fixtures
• Updated tests/test_path.py and tests/test_config/test_assets.py (removed OverrideProvider and pkg_resources mocks)
• Manual check: override_asset() still works for static views, i18n translation dirs, and cache busters
• Manual check: apps installed from wheels/eggs can still resolve template and static paths

Documentation

• Updated docs/narr/assets.rst, docs/narr/extending.rst, docs/narr/environment.rst, and docs/glossary.rst
• Added entries to CHANGES.rst under Features and Backward Incompatibilities