Remove unused components and models for improved maintainability

- Deleted redundant components (`AddActionButton`, `AlertBox`, `AlertStack`, `BackButton`, `CancelButton`, and `CollapsableArea`) and related files.
- Removed unused models (`Book`, `BookSerie`, `BookTables`, `Character`, and `Chapter`) to reduce codebase clutter.
- Updated project structure and references to reflect these removals.

components/book/settings/BookSetting.tsx

@@ -2,8 +2,8 @@
 import {useState} from "react";
 import BookSettingSidebar from "@/components/book/settings/BookSettingSidebar";
 import BookSettingOption from "@/components/book/settings/BookSettingOption";
-import SettingsPanel from "@/components/SettingsPanel";
-import {useTranslations} from "next-intl";
+import SettingsPanel from "@/components/ui/SettingsPanel";
+import {useTranslations} from '@/lib/i18n';
 
 interface BookSettingProps {
     onClose: () => void;
@@ -19,7 +19,7 @@ export default function BookSetting({onClose}: BookSettingProps) {
             sidebar={<BookSettingSidebar selectedSetting={currentSetting} setSelectedSetting={setCurrentSetting}/>}
             onClose={onClose}
         >
-            <BookSettingOption setting={currentSetting}/>
+            <BookSettingOption key={currentSetting} setting={currentSetting}/>
         </SettingsPanel>
     );
 }