The live host published receipts reading `measured_uj: 3300,
provenance: HwShunt` — a constant stub mislabelled as a hardware
measurement. Three fixes, root-cause first:
1. joule-ui-interaction: `Meter::provenance()` joins the trait
(defaults `HwShunt`, `NoMeter` overrides to `Estimator`).
`run_interaction` now tags the metered energy with the meter's
*declared* provenance instead of inferring `HwShunt` from `Some(_)`.
A meter cannot accidentally promote an estimate to a measurement.
2. joule-ui-serve: the live demo drops the `DemoMeter` stub for the
real Sandbox `PowerMeter` (IOReport/RAPL), and the handler does
intensity-scaled real CPU work — so every receipt's `HwShunt` is
true and the joules genuinely vary with the work. No hardware ⇒
honest `Estimator`, never a faked figure.
3. sandbox-meter: `IoReportProbe` is `Send` (CF objects, mutex-guarded
single-thread access), so the real `PowerMeter` can live in the
concurrent worker-pool `Host`.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
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