SliderControl (which drives the auto-inspector's ~144 fields and most custom
panels) previously ignored the viewer unit preference and always rendered raw
meters with a static "m" label, while MetricControl converted to feet — so
toggling imperial changed some length inputs and not others. Extract the
conversion into a shared `useLinearDisplay(unit, precision)` hook and route
BOTH controls through it, so every `unit="m"` length field displays and edits
in feet when imperial and meters when metric — consistently.
Values are always stored in meters; only display, the text field, and drag/
wheel/arrow deltas move to the display unit. For metric and non-length units
(°, %, in, …) the conversions are the identity, so those paths are unchanged.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
