feat: add note width modes

src/utils/noteWidth.ts

@@ -0,0 +1,23 @@
+import type { NoteWidthMode } from '../types'
+
+export const DEFAULT_NOTE_WIDTH_MODE: NoteWidthMode = 'normal'
+
+export function normalizeNoteWidthMode(value: unknown): NoteWidthMode | null {
+  if (typeof value !== 'string') return null
+
+  const normalized = value.trim().toLowerCase()
+  return normalized === 'normal' || normalized === 'wide' ? normalized : null
+}
+
+export function resolveNoteWidthMode(
+  noteWidth: unknown,
+  defaultWidth: unknown,
+): NoteWidthMode {
+  return normalizeNoteWidthMode(noteWidth)
+    ?? normalizeNoteWidthMode(defaultWidth)
+    ?? DEFAULT_NOTE_WIDTH_MODE
+}
+
+export function toggleNoteWidthMode(width: unknown): NoteWidthMode {
+  return resolveNoteWidthMode(width, DEFAULT_NOTE_WIDTH_MODE) === 'wide' ? 'normal' : 'wide'
+}