feat: artist/page endpoint, multi-disc fix, playlist ownership, UX improvements

- Switch artist view to artist/page API (proper sections: Albums, Singles & EPs,
  Live, Compilations; version in titles like "Deluxe")
- Fix artist sections categorization using releases[].type from artist/page
- Add getUser() backend call; fetch on session restore when userId=0 to fix
  playlist ownership (Remove from playlist / Delete playlist were missing)
- Fix multi-disc double-click / Play Now queue start index (disc headers were
  counted in row index but excluded from currentTracksJson)
- Hide redundant Album column when viewing an album
- Make artist name in context header clickable (navigates to artist page)
- Fix gap between title and artist name in context header (addStretch)
- Fix queue panel track titles to include version field
- Fix album list to show version in title column

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

rust/include/qobuz_backend.h

@@ -34,6 +34,7 @@ enum QobuzEvent {
     EV_PLAYLIST_CREATED      = 20,
     EV_PLAYLIST_DELETED      = 21,
     EV_PLAYLIST_TRACK_ADDED  = 22,
+    EV_USER_OK               = 23,
 };
 
 // Callback signature
@@ -46,6 +47,7 @@ void                qobuz_backend_free(QobuzBackendOpaque *backend);
 // Auth
 void qobuz_backend_login(QobuzBackendOpaque *backend, const char *email, const char *password);
 void qobuz_backend_set_token(QobuzBackendOpaque *backend, const char *token);
+void qobuz_backend_get_user(QobuzBackendOpaque *backend);
 
 // Catalog
 void qobuz_backend_search(QobuzBackendOpaque *backend, const char *query, uint32_t offset, uint32_t limit);