ExtPay SDK — upstream license declarations and corresponding source

Dependency: extpay 3.1.2, installed from npm and pinned in package-lock.json.
Upstream project: https://github.com/Glench/ExtPay
Upstream package: https://www.npmjs.com/package/extpay/v/3.1.2

The published package has conflicting declarations:
- package.json license field: AGPL-3.0-or-later
- package LICENSE file: LGPL-3.0 (the entire file contains this identifier)

These declarations are reproduced as supplied by upstream. This notice does
not resolve the discrepancy or select a license for CiteExport Pro itself.
The publisher must confirm the applicable upstream license before public
distribution and provide recipients with a public corresponding-source link.

This project does not modify the installed ExtPay source files. Vite bundles
and minifies the SDK and the webextension-polyfill dependency for the extension;
those transformations are generated from the supplied source and build scripts.

The matching CiteExport-Pro-Source.zip includes this application's build inputs
and exact copies of the installed extpay 3.1.2 source/build inputs under:
  notebooklm-cite-exporter/third-party/extpay-3.1.2/
That directory preserves package.json, LICENSE, ExtPay.dev.js, distribution
files, dependency/build manifests and upstream documentation. Unrelated native
platform examples, screenshots and editor swap files are omitted. The archive's
root package-lock.json records the exact installed application dependencies.
No application or system credentials are required to read that source archive.

Complete, verbatim standard license texts are included for reference:
- AGPL-3.0.txt: https://www.gnu.org/licenses/agpl-3.0.txt
- LGPL-3.0.txt: https://www.gnu.org/licenses/lgpl-3.0.txt
These two files were retrieved directly from the stated GNU URLs.
GPL-3.0.txt preserves the entire GNU GPL version 3 license section, including
all 17 sections and END OF TERMS AND CONDITIONS, from the installed jszip
3.10.1 LICENSE.markdown without changing its text. That upstream copy does not
include the optional "How to Apply These Terms" appendix. The GNU reference
URL is https://www.gnu.org/licenses/gpl-3.0.txt; direct retrieval of that file
timed out. GPL version 3 is included because LGPL version 3 incorporates its
terms; this reference copy does not choose GPL over JSZip's MIT alternative.
Providing these texts does not itself settle the upstream license discrepancy.
