HEIC decoder: source notice

This site uses heic-to 1.6.6 (unmodified upstream CSP build), dynamically loaded
only when a HEIC image is read. The upstream package is LGPL-3.0-or-later.

Package source and build instructions:
https://github.com/hoppergee/heic-to
https://www.npmjs.com/package/heic-to/v/1.6.6

The package release identifies libheif 1.23.6 as its decoder dependency.
Underlying project source and license notices:
https://github.com/strukturag/libheif/tree/v1.23.6
https://github.com/strukturag/libheif/blob/v1.23.6/COPYING
https://github.com/strukturag/libde265

The decoder is a separate generated JavaScript asset; the application does not
modify the upstream decoder. The heic-to README describes rebuilding the CSP
variant and its dependencies. The accompanying heic-to.txt preserves the
upstream package license notice. GNU license texts are available at:
https://www.gnu.org/licenses/lgpl-3.0.html
https://www.gnu.org/licenses/gpl-3.0.html