Status checks asked is_spotify_authenticated() (official OAuth only) instead of
is_spotify_metadata_available(), so a Spotify-Free primary read as disconnected.
get_primary_source_status had spotify_free awareness but it was dead code:
get_client_for_source('spotify') returns None unless officially authed, so the
free-availability probe never had a client. Fetch the client directly for that
check; add the missing free branch to the dashboard test message. Seam + regression tests.
