feat(constructor): Add nodeIDs set

[Sirivasv]

Fixes #27

[Copilot]

Pull Request Overview

This PR adds a nodeIDs property to the BMSSP constructor that stores unique node identifiers from the input graph edges as a Set.

• Introduces a nodeIDs Set property to track unique node identifiers
• Updates the constructor to populate the Set while processing edges
• Adds comprehensive test coverage for the new functionality

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/bmssp.mjs	Adds nodeIDs Set property and populates it during edge processing
test/main.test.mjs	Adds test suite to verify nodeIDs Set contains correct unique node identifiers

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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