Integrate local database management and IPC handlers into Electron

- Add comprehensive IPC handlers for database operations like books, chapters, characters, and conversations.
- Implement local database initialization and user data encryption.
- Update preload script paths for consistent environment handling.
- Modify `page.tsx` to initialize local database within Electron environment.
- Add new dependencies including `node-sqlite3-wasm` and `electron-rebuild`.

components/ScribeTopBar.tsx

@@ -2,6 +2,7 @@
 import {useContext} from "react";
 import {BookContext, BookContextProps} from "@/context/BookContext";
 import {useTranslations} from "next-intl";
+import OfflineToggle from "@/components/offline/OfflineToggle";
 
 export default function ScribeTopBar() {
     const book: BookContextProps = useContext(BookContext);
@@ -33,6 +34,7 @@ export default function ScribeTopBar() {
                 </div>
             )}
             <div className="flex items-center space-x-2 min-w-[120px] justify-end">
+                <OfflineToggle />
             </div>
         </div>
     )