[mikegit123git]

Summary

Fixes #1593.

Fix a panic in misra_gries_edge_color() when used with Petgraph's UnGraphMap.

Undirected GraphMap adjacency iterators may return edge references with a reversed orientation relative to their canonical stored edge IDs. Direct edge index lookup can therefore panic with edge not found.

Changes

• Build a mapping from canonical edge IDs to internal indices.
• Add endpoint-based fallback for reversed edge references.
• Preserve parallel-edge identity through exact edge ID lookup.
• Detect ambiguous endpoint mappings.
• Use unified edge indexing for color reads and updates.
• Keep the public API unchanged.

Regression Tests

Added coverage for:

• Original two-edge UnGraphMap reproducer.
• Reversed edge insertion.
• Triangle with reversed edge orientations.
• Five-node complete graph (K5).
• StableGraph parallel edges.
• StableGraph sparse edge indices.

Validation

All local checks passed:

• cargo test -p rustworkx-core: 536 tests passed.
• cargo fmt --all -- --check: passed.
• cargo clippy -p rustworkx-core --all-targets -- -D warnings: passed.
• git diff --check: passed.

[CLAassistant]

All committers have signed the CLA.