feat: make each plugin an npm workspace built by a termix-plugin CLI

plugins/network-topology/src/frontend/index.mjs

@@ -0,0 +1,37 @@
+/**
+ * Frontend half of the network-topology plugin.
+ *
+ * NetworkGraphCard renders in two modes: as a full tab (network_graph) and
+ * embedded as a dashboard card. Both usages are wired today through the
+ * existing tabUtils.tsx / DashboardTab.tsx switch statements the same way
+ * fleet-inventory's tab is, not through register() below -- per
+ * src/ui/shell/pluginLoader.ts's own comment, "there is no plugin loader
+ * yet" for the frontend half.
+ *
+ * register()/unregister() still follow the same shape every other plugin's
+ * frontend entry does, so this is ready the moment a real frontend plugin
+ * loader exists.
+ */
+
+export const id = "network-topology";
+export const tabId = "network_graph";
+
+export async function register({ registerRailItem, registerTabComponent, icons }) {
+  registerTabComponent?.(tabId, () =>
+    import("./NetworkGraphCard.tsx").then((m) => ({
+      default: m.NetworkGraphCard,
+    })),
+  );
+
+  registerRailItem?.({
+    id: tabId,
+    icon: icons.Network,
+    labelKey: "nav.networkGraph",
+    kind: "tab",
+  });
+}
+
+export async function unregister({ unregisterRailItem, unregisterTabComponent }) {
+  unregisterRailItem?.(tabId);
+  unregisterTabComponent?.(tabId);
+}