- Duplicate `spotify` key in saveSettings() object literal caused
second definition (embed_tags/tags) to silently overwrite the first
(client_id/client_secret/redirect_uri), destroying credentials on
every save. Merged into single key.
- authenticateSpotify() and authenticateTidal() now await saveSettings()
before opening auth window, ensuring credentials are persisted.
- Tidal auth now dynamically sets redirect_uri from request host for
LAN/Docker users and stores it in tidal_oauth_state so the callback
token exchange uses the same URI.
Fixes#191
0a3cca4f1f
