WaitForInstanceState now aborts immediately with the recorded StateReason
message when it observes a reaped state (shutting-down/terminated) while
waiting for a live target, instead of burning the full 5-minute timeout on
an instance that can never reach it.
MarkFailed takes a context and records the failure on the active span via
span.RecordError so a reaped launch surfaces in the APM error stream,
correlated by trace id. Only the LaunchRunInstances path carries a live
span; other callers pass context.Background() and the record is a no-op.
Surfaced by RCA of E2E run 29258398516 (TestAccountScoping/Step2).
Josh Siviour
369025f86e