Frontend half of the two-PR split on the systemd restart-bound work
(clause 2): once a container's unit hits systemd's bounded restart
limit and stops on its own, that read exactly like a deliberate stop
("not running") — no way to tell "gave up" from "off on purpose".
Renders ContainerView.failed as a distinct red "gave up" badge on the
container row, in place of the muted "not running" badge. Both states
have running: false; failed is the new orthogonal fact that tells them
apart, same "independent flags, no state machine" shape as
paused/needs_update/needs_login. An older backend without the field
serves failed: undefined, which reads falsy, so this degrades cleanly
to the existing single "not running" badge.
Frontend-only — no Rust changes. Safe to merge in either order
relative to the backend PR carrying ContainerView.failed itself.