feat: createBackend, createPreload, createRenderer

Introduced the mentioned helper methods in order to help split big plugins into manageable chunks.

src/plugins/captions-selector/back.ts

@@ -0,0 +1,28 @@
+import prompt from 'custom-electron-prompt';
+
+import promptOptions from '@/providers/prompt-options';
+import { createBackend } from '@/utils';
+
+export default createBackend({
+  start({ ipc: { handle }, window }) {
+    handle(
+      'captionsSelector',
+      async (captionLabels: Record<string, string>, currentIndex: string) =>
+        await prompt(
+          {
+            title: 'Choose Caption',
+            label: `Current Caption: ${captionLabels[currentIndex] || 'None'}`,
+            type: 'select',
+            value: currentIndex,
+            selectOptions: captionLabels,
+            resizable: true,
+            ...promptOptions(),
+          },
+          window,
+        ),
+    );
+  },
+  stop({ ipc: { removeHandler } }) {
+    removeHandler('captionsSelector');
+  },
+});