fix(ui): correct imports, guard checks, logging and settings handling

apps/electron-backend/src/app/api/main.preload.ts

@@ -8,6 +8,10 @@ contextBridge.exposeInMainWorld('electron', {
     updatePlaylistFromFilePath: (filePath: string, title: string) =>
         ipcRenderer.invoke('update-playlist-from-file-path', filePath, title),
     openPlaylistFromFile: () => ipcRenderer.invoke('open-playlist-from-file'),
+    saveFileDialog: (defaultPath: string, filters?: { name: string; extensions: string[] }[]) =>
+        ipcRenderer.invoke('save-file-dialog', defaultPath, filters),
+    writeFile: (filePath: string, content: string) =>
+        ipcRenderer.invoke('write-file', filePath, content),
     setUserAgent: (userAgent: string, referer?: string) =>
         ipcRenderer.invoke('set-user-agent', userAgent, referer),
     openInMpv: (