Fix plugins not showing in admin panel

API route at /api/admin/plugins imports pluginRegistry from @/lib/plugins
but the loader (which registers all plugins) was only imported in admin-nav.ts.
Import loader in index.ts so it runs for any consumer of the plugins module.

src/lib/plugins/index.ts

@@ -1,3 +1,5 @@
+import "./loader";
+
 export { pluginRegistry } from "./registry";
 export type {
 	PluginDefinition,