the hive dashboard uses the swarm UI's links menu, beside the profile avatar

The links menu moves into @hive/shared and takes its links as a prop. The swarm
UI feeds it /api/links as before; the dashboard feeds it stats, API docs and the
swarm, and mounts it next to the profile menu in place of its own hamburger on
the left. A link opens in a new tab unless its entry says it is a page of the
same site.

frontend/packages/shared/src/links-menu/links.ts

@@ -0,0 +1,25 @@
+// What the links menu shows for one link, without a DOM: where it opens and
+// what it is called. Shared by the swarm UI (its `/api/links`) and the hive
+// dashboard (its stats and API docs pages, and the swarm UI).
+
+/** One entry of the links menu. */
+export interface MenuLink {
+  label: string;
+  /** A glyph before the label; none leaves the label alone. */
+  icon?: string;
+  url: string;
+  /**
+   * Opens in a new tab. Defaults to true: a link the menu was handed from
+   * elsewhere (the swarm's service list) leaves the page. A page of the
+   * same site says `false` and opens in place.
+   */
+  external?: boolean;
+}
+
+/** The anchor attributes that make a link open where its entry says. */
+export function linkAttrs(link: MenuLink): {
+  target?: string;
+  rel?: string;
+} {
+  return link.external === false ? {} : { target: "_blank", rel: "noreferrer" };
+}