Add auth key reissue handling to k8s-proxy, mirroring containerboot.
When the proxy detects an auth failure (login-state health warning or
NeedsLogin state), it disconnects from control, signals the operator
via the state Secret, waits for a new key, clears stale state, and
exits so Kubernetes restarts the pod with the new key.
A health watcher goroutine runs alongside ts.Up() to short-circuit
the startup timeout on terminal auth failures.
Updates #14080
Signed-off-by: chaosinthecrd <tom@tmlabs.co.uk>
e6cfd9f7f3