refactor: remove legacy theme handling and streamline plugin initialization

src/plugins/index.ts

@@ -16,7 +16,6 @@ pluginManager.registerPlugin(themesPlugin);
 
 // Legacy plugin exports
 export { init as Monofile } from './monofile';
-export { init as Themes } from './themes';
 
 export async function initializePlugins(): Promise<void> {
   await pluginManager.startAllPlugins();

src/plugins/themes.ts

@@ -1,5 +0,0 @@
-import { enableCurrentTheme } from "@/seqta/ui/themes/enableCurrent";
-
-export async function init() {
-  enableCurrentTheme();
-}