ProcessMeter's docs justified billing an estimated fallback span with this
crate's EstimatorMeter by the host meter's window taking in the span meter's
GPU-rail waits. jouleclaw-energy now reads the host meter inside the GPU
snapshots, so that window is the work's own and the reason no longer holds.
The behaviour is unchanged (an estimated request is still billed by this
crate's estimator over the work's window, as the rest of a partial span is);
the comments now say so instead of describing the old window.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
9a6c28ff39