The filter strip was passing the Invidious instance URL as serverURL to
AvatarURLBuilder, which built a Yattee Server-style /avatar/ path that
doesn't exist on Invidious. Now passes the actual Yattee Server URL
(matching SubscriptionsView pattern) and enriches channels from
CachedChannelData as a fallback when the API doesn't return thumbnails.
e51ebd7ab2