- Light panel: HDR switch, headroom limit and an SDR Rendition flyout
(shown with HDR on); Visualize HDR beside the switch.
- `Overlay::HdrRange` / `view.visualizeHdr`: the SDR render dimmed to grey,
with pixels the HDR rendition puts above SDR white painted in four bands by
stops above it. Rendered on the CPU from the float HDR render.
- Export dialog: "HDR output" for JPEG (gain map) and 32-bit TIFF.
- Parity (Q. HDR 2 ✅ 3 🟡, LR-EDIT-HDR-MODE ✅, LR-EXP-HDR 🟡), README, ROADMAP.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>