The Hidden and Blocked tabs were a bare row of name chips ("two withered
chips"). Both now render a responsive grid of real channel cards via a shared
ExcludedChannelList: avatar + name + open-on-YouTube (reusing ChannelLink) and
one labelled reversing action (Unhide / Unblock). One presentation, parameterised
by icon/label/action/copy — the two "excluded channel" tabs now match.
Gate green: tsc/eslint-0/prettier/knip clean. Self-E2E'd: Hidden tab renders both
channels as cards with avatars, YT links, and Unhide buttons.
