feat: implemented global key signature track

src/core/global-track/KGGlobalTrack.ts

@@ -1,5 +1,6 @@
 import { Expose, Type } from 'class-transformer';
 import { KGGlobalRegion } from '../region/KGGlobalRegion';
+import { KGKeySignatureRegion } from '../region/KGKeySignatureRegion';
 import { KGMarkerRegion } from '../region/KGMarkerRegion';
 
 export enum GlobalTrackType {
@@ -32,6 +33,7 @@ export class KGGlobalTrack {
       subTypes: [
         { value: KGGlobalRegion, name: 'KGGlobalRegion' },
         { value: KGMarkerRegion, name: 'KGMarkerRegion' },
+        { value: KGKeySignatureRegion, name: 'KGKeySignatureRegion' },
       ],
     },
   })

src/core/global-track/KGSignatureTrack.ts

@@ -5,7 +5,7 @@ export class KGSignatureTrack extends KGGlobalTrack {
   @Expose()
   protected override __type: string = 'KGSignatureTrack';
 
-  constructor(id: string = 'global-signature', trackIndex: number = 2, name: string = 'Signature') {
+  constructor(id: string = 'global-signature', trackIndex: number = 2, name: string = 'Key Signature') {
     super(id, trackIndex, GlobalTrackType.Signature, name, []);
     this.__type = 'KGSignatureTrack';
   }