Add page deletion functionality with confirmation dialog and API endpoin

lib/db-actions.ts

@@ -141,4 +141,8 @@ export async function getNextPageNumber(storyId: string): Promise<number> {
   }
 
   return Math.max(...storyPages.map(p => p.pageNumber)) + 1;
+}
+
+export async function deletePage(pageId: string): Promise<void> {
+  await db.delete(pages).where(eq(pages.id, pageId));
 }