switch to monorepo structure

packages/core/src/bookmark.ts

@@ -0,0 +1,18 @@
+type BookmarkKind = "link" | "placeholder"
+
+interface LinkBookmark {
+	kind: "link"
+	id: string
+	title: string
+	url: string
+}
+
+interface PlaceholderBookmark {
+	id: string
+	kind: "placeholder"
+}
+
+type Bookmark = LinkBookmark | PlaceholderBookmark
+type BookmarkId = Bookmark["id"]
+
+export type { Bookmark, BookmarkId, BookmarkKind, LinkBookmark }