Aurora SpotiRip desktop and web app

- Spotify playlist, library, album and artist browsing with in-app playback
- Song, playlist and album downloads via spotdl with YouTube and Bandcamp fallbacks
- Electron desktop app (castLabs Widevine) with a permanent sidebar layout
- Linux and Windows packaging scripts

helpers/desktopBridge.tsx

@@ -0,0 +1,10 @@
+export type DesktopBridge = {
+  getDownloadFolder: () => Promise<string>;
+  chooseDownloadFolder: () => Promise<string | undefined>;
+  showInFolder: (path: string) => Promise<void>;
+};
+
+export function getDesktopBridge(): DesktopBridge | undefined {
+  if (typeof window === "undefined") return undefined;
+  return (window as typeof window & { spotiripDesktop?: DesktopBridge }).spotiripDesktop;
+}