feat(plugin): support enterprise extension (#861)

electron/extensions/builtin/diagnostics.ts

@@ -0,0 +1,25 @@
+import type {
+  Extension,
+  ExtensionContext,
+  HostApiRouteExtension,
+  RouteHandler,
+} from '../types';
+
+class DiagnosticsExtension implements HostApiRouteExtension {
+  readonly id = 'builtin/diagnostics';
+
+  setup(_ctx: ExtensionContext): void {
+    // Diagnostics routes are stateless; no setup needed.
+  }
+
+  getRouteHandler(): RouteHandler {
+    return async (req, res, url, ctx) => {
+      const { handleDiagnosticsRoutes } = await import('../../api/routes/diagnostics');
+      return handleDiagnosticsRoutes(req, res, url, ctx);
+    };
+  }
+}
+
+export function createDiagnosticsExtension(): Extension {
+  return new DiagnosticsExtension();
+}