render: bounded cooperative HDR input foundation (#837)

A cancellable, bounded Radiance HDR decoder for render lighting input; reference images still accept PNG and JPEG only.

ATTRIBUTION.md

@@ -86,6 +86,16 @@ Generated-in-code assets are original and have no file to list:
 | LICENSE-MIT, LICENSE-APACHE (licence text) | CADCraft | — |
 | .github/workflows/release.yml, .github/workflows/packaging-lint.yml and packaging/ (release pipeline: Linux AppImage/deb/rpm/Flatpak/tar.gz, FreeBSD, macOS dmg, Windows MSI/portable zip, web zip; AppRun, nfpm, Flatpak, WiX and Info.plist templates) | PhotoCraft (https://github.com/storytold/photocraft) `.github/workflows/{release,packaging-lint}.yml`, `packaging/` | Apache-2.0 |
 
+## Incremental HDR codec adapter
+
+`crates/render/src/lighting/hdr.rs` adapts the scanline/component/old-RLE decoding
+state machines from the Radiance decoder in `image` 0.25.10
+([source](https://docs.rs/crate/image/0.25.10/source/src/codecs/hdr/decoder.rs)),
+MIT OR Apache-2.0. Metadata parsing still uses that library. The adapter makes row
+work cooperative and adds checked run lengths, zero-run rejection, width validation,
+header/input/radiance bounds and cancellation. Original licence texts are retained
+in THIRD-PARTY-LICENSES.txt; no images or artwork from that project are copied.
+
 ## Recovered contributions
 
 | SolidCraft file | Original contribution | Licence |