basic abc frontend support

frontend/package-lock.json

@@ -13,6 +13,7 @@
         "@magenta/music": "^1.23.1",
         "@microsoft/fetch-event-source": "^2.0.1",
         "@primer/octicons-react": "^19.1.0",
+        "abcjs": "^6.2.3",
         "chart.js": "^4.3.0",
         "classnames": "^2.3.2",
         "file-saver": "^2.0.5",
@@ -2690,6 +2691,15 @@
       "integrity": "sha512-nne9/IiQ/hzIhY6pdDnbBtz7DjPTKrY00P/zvPSm5pOFkl6xuGrGnXn/VtTNNfNtAfZ9/1RtehkszU9qcTii0Q==",
       "optional": true
     },
+    "node_modules/abcjs": {
+      "version": "6.2.3",
+      "resolved": "https://registry.npmjs.org/abcjs/-/abcjs-6.2.3.tgz",
+      "integrity": "sha512-epu8C1yRkxV7Ss9hS0Bu72rairl1p2sR3hviVowjtdDJvb5GRE0SrB4TtN4HBbaoYhvxGnSZQxGULfQlW3o3RQ==",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/paulrosen"
+      }
+    },
     "node_modules/acorn": {
       "version": "7.4.1",
       "resolved": "https://registry.npmjs.org/acorn/-/acorn-7.4.1.tgz",