[Bug] Add Unit Tests for `musicutils.js` — Core Music Constants & Utilities Are Untested

[swapnachoudhary43]

Current Behavior

js/utils/musicutils.js is one of the most critical files in the entire MusicBlocks codebase — it contains all core music constants (SOLFEGENAMES, NOTENAMES, ALLNOTENAMES, scales, modes, etc.) and utility functions used across every other block file. Despite this, it currently has 0% unit test coverage.

This means:

• Regressions in note/pitch/solfege data go completely undetected by CI
• Contributors cannot safely refactor or extend music utility logic
• Any changes to constants like SOLFEGENAMES1 or NOTENAMES risk breaking the entire app silently

Desired Situation

Create a new test file __tests__/utils/musicutils.test.js that covers the core exported constants and utility functions in musicutils.js, including:

• NOTENAMES array contains exactly the 7 expected note letters (C, D, E, F, G, A, B)
• SOLFEGENAMES1 array contains all 7 base solfege syllables (do, re, mi, fa, sol, la, ti)
• ALLNOTENAMES array includes sharps, flats, double accidentals
• Solfege names do not contain duplicates for base syllables
• Pitch/note name arrays are non-empty and of correct type (Array of strings)
• Boundary checks: first and last elements of NOTENAMES and SOLFEGENAMES1 are correct
• Mode definitions (e.g. major, minor) exist and have correct step counts (7 steps)
• Each mode's steps sum to 12 (one full octave of semitones)

Acceptance Criteria

• A new file __tests__/utils/musicutils.test.js is created
• All listed test cases pass with npm test
• Coverage for musicutils.js increases meaningfully (target ≥ 60%)
• No existing tests are broken
• Code follows the project's existing Jest testing conventions (see docs/TESTING.md)

Additional Context

• musicutils.js is 4,427 lines — the 3rd largest JS file in the codebase
• It is imported/used by PitchBlocks.js, RhythmBlocks.js, MeterBlocks.js, IntervalsBlocks.js, and many widgets
• A similar issue was opened for FlowBlocks.js (Add tests for FlowBlocks #4829) — this follows the same initiative but targets the foundational music utility layer
• Maintainers have explicitly requested more unit tests in v3.6.2 release notes

Checklist

✅ I have read and followed the project's code of conduct.
✅ I have searched for similar issues before creating this one.
✅ I have provided all the necessary information to understand and reproduce the issue.
✅ I am willing to contribute to the resolution of this issue.