Qobuz API now requires intent=stream parameter for stream URL requests,
and the app_secret must be extracted using the Spoofbuz decoding method
from bundle.js rather than plain-text values.
Changes:
- Add intent=stream parameter to stream URL requests
- Add QobuzCredentialFetcher class to extract credentials from web player
- Add "Fetch Credentials" button to Qobuz settings page
- Decode obfuscated app secrets using seed/timezone/info/extras method
This fixes "Invalid Request Signature" errors that prevented playback.
