PicPropper — replacing the LGPL HEIC decoder

The application-relink.tar.gz download contains the compiled HTML, JavaScript,
styles, library binaries, and notices from this release. It does not include
the original application source, tests, or application build configuration.
The application license expressly permits recombination and debugging of
modified LGPL libraries. See application-license.txt.

1. Extract application-relink.tar.gz into an empty directory.
2. Obtain decoder-source.tar.gz from https://picpropper.com/source/decoder-source.tar.gz.
   It contains exact library sources, modifications, and the decoder build tools.
   Follow vendor/libheif/README.md and the source bundle's build instructions.
3. Replace vendor/libheif/libheif.mjs and vendor/libheif/libheif.wasm together
   with the rebuilt pair. Preserve the documented decoder JavaScript interface.
   The application loads these paths at runtime; there is no signature check,
   content hash check, or need to rebuild the application.
4. Serve the extracted directory at the root of a local HTTP server. For
   example, with Python 3 installed: python3 -m http.server 8080 --bind 127.0.0.1
5. Open http://127.0.0.1:8080/heic-to-jpg/ in a browser, select a HEIC image,
   and convert it. Use a fresh browser profile or clear cached files after
   replacing the library. Inspect the worker's network requests to confirm
   it loads your local libheif.mjs and libheif.wasm.

The compiled files are the Corresponding Application Code supplied for
recombination under LGPLv3 section 4(d)(0). The separately available decoder
source bundle and library license texts supply the library source/notices.
The original site's full source archive is no longer distributed. Third-party
license grants remain unchanged. This kit does not grant a general license
to republish the PicPropper application or branding.