KeySet objects support for filter_algorithms and guess_alg

[azmeuk]

Another convenience PR. This makes filter_algorithms able to find all the algs in a KeySet and guess_alg able to find the best fitting alg in the whole KeySet.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (70deabb) to head (775d53b).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

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##              main       #81   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           47        47           
  Lines         2849      2856    +7     
  Branches       320       324    +4     
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+ Hits          2849      2856    +7     

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unittests	100.00% <100.00%> (ø)

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[Copilot]

Pull request overview

This PR extends the filter_algorithms method in JWSRegistry to accept KeySet objects in addition to individual key instances, enabling convenient filtering of algorithms across multiple keys at once.

• Adds KeySet support to filter_algorithms with recursive algorithm aggregation and deduplication
• Includes comprehensive test coverage for the new functionality
• Updates documentation to reflect the API enhancement

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/joserfc/_rfc7515/registry.py	Implements KeySet handling in filter_algorithms by recursively processing each key and deduplicating results
tests/jws/test_registry.py	Adds test case verifying filter_algorithms works with KeySet containing multiple RSA and EC keys
docs/changelog.rst	Documents the new feature in the unreleased 1.x.x section

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[Copilot]

The deduplication logic using if alg not in rv performs a linear search through the list for each algorithm, resulting in O(n²) time complexity. For KeySets with many keys, this could be inefficient. Consider using a set to track seen algorithm names and only append to rv if the algorithm name hasn't been seen yet:

if isinstance(key, KeySet):
    seen_names = set()
    for k in key.keys:
        for alg in cls.filter_algorithms(k, names):
            if alg.name not in seen_names:
                seen_names.add(alg.name)
                rv.append(alg)
    return rv

Suggested change

	for k in key.keys:
	for alg in cls.filter_algorithms(k, names):
	if alg not in rv:
	seen_names = set()
	for k in key.keys:
	for alg in cls.filter_algorithms(k, names):
	if alg.name not in seen_names:
	seen_names.add(alg.name)