Add guards for metavariable occurence, and sorting rule candidates by n constants

[psaegert]

… n constants

[Copilot]

Pull request overview

This PR adds termination/pruning guards around rule discovery and maintenance in SimpliPy, aiming to avoid non-terminating metavariable expansions and reduce redundant explicit rules.

Changes:

• Add violates_wildcard_multiplicity(...) and use it during rule discovery to filter unsafe candidates, while also preferring candidates with fewer '<constant>' tokens.
• Introduce SimpliPyEngine.prune_redundant_rules() and invoke it after rule discovery; add a CLI prune-rules command.
• Update tests for pruning/multiplicity behavior and bump project version to 0.2.15.

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/test_engine_simplification.py	Adds tests for rule pruning and wildcard multiplicity guard.
src/simplipy/utils.py	Adds wildcard multiplicity checker helper.
src/simplipy/engine.py	Adds redundant-rule pruning, integrates multiplicity guard + candidate sorting in rule finder, and runs pruning after rule discovery.
src/simplipy/__main__.py	Adds prune-rules CLI command.
README.md	Version bump to 0.2.15.
pyproject.toml	Version bump to 0.2.15.
.gitignore	Ignore .vscode/.
.github/copilot-instructions.md	Removes Copilot instruction file.

Comments suppressed due to low confidence (1)

tests/test_engine_simplification.py:120

• Lines 117–124 are indented as part of the TestPruneRedundantRules class body but are not inside a test_... method. This will execute at import/class-definition time and will likely break test collection (and/or perform a networked SimpliPyEngine.load(...) during import). Wrap this block in a test function/method (e.g. def test_repeated_addition_...) and ensure the indentation is correct so it’s not executed at class scope.

        assert len(engine.simplification_rules) == 2
    engine = SimpliPyEngine.load("dev_7-3", install=True)
    expr = " + ".join(["x"] * 14)

    simplified = engine.simplify(expr, max_iter=1, verbose=False)