Refactor/mode pitch collections aliases

[Siddharth-732]

fixes #5921

Summary

Refactors musical mode definitions in musicutils.js from a large flat MUSICALMODES map into canonical pitch collections plus alias mappings.

Changes

• Added grouped canonical definitions in PITCH_COLLECTIONS (organized by note count).
• Added PITCH_COLLECTION_ALIASES for equivalent mode names.
• Rebuilt MUSICALMODES programmatically from canonical collections + aliases.
• Kept MUSICALMODES["custom"] override behavior unchanged.
• Removed the inline TODO about organizing/naming pitch collections.

Behavior/compatibility

• No intended functional changes.
• Existing lookups via MUSICALMODES[name] continue to work.
• Alias names resolve to the same interval patterns as before.

Validation

• A manual check was done to ensure no error in functionality.
• Lint run completed.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[Siddharth-732]

@omsuneri, please review this when you have a moment.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.