Add support for registering vendor asset routes

src/util/support/path.ts

@@ -497,14 +497,14 @@ export class UniversalPath {
      * Get the mime-type of this resource.
      */
     get mimeType(): string | false {
-        return mime.lookup(this.resourceLocalPath)
+        return mime.lookup(this.toBase)
     }
 
     /**
      * Get the content-type header of this resource.
      */
     get contentType(): string | false {
-        return mime.contentType(this.resourceLocalPath)
+        return mime.contentType(this.toBase)
     }
 
     /**