Ticket #19 (spec #16): fixed three-metric protocol as a runnable script
(idle memory both keep-alive states, wake latency from debug logs,
real-time factor on the fixed 30 s sample per backend) plus per-rung
load footprints, portal/direct injection probe, and threshold
derivation for the model-ladder ticket (#20). Offline unit tests for
the parsing/statistics/report helpers. Evidence recorded on the ticket.
One debug-only marker (Toggle requested in state ...) makes wake
latency derivable from logs alone.
