chore: enable cors for sfc as temporary fix

packages/sfc-playground/public/_headers

@@ -1,3 +0,0 @@
-/assets/*
-  cache-control: max-age=31536000
-  cache-control: immutable

packages/sfc-playground/vercel.json

@@ -0,0 +1,8 @@
+{
+  "headers": [
+    {
+      "source": "/(.*).js",
+      "headers": [{ "key": "Access-Control-Allow-Origin", "value": "*" }]
+    }
+  ]
+}