Third-party notices for ck-client.

Cloak `ck-client` (manifest: `manifest.json`; release `v2.12.0`; source commit [`c3d5470ef76bba68d7812f5d06e4181dc1b1a5d6`](https://github.com/cbeuw/Cloak/commit/c3d5470ef76bba68d7812f5d06e4181dc1b1a5d6); binary metadata: Go `go1.24.5`, darwin/arm64, clean VCS revision).
The direct Cloak license is in `LICENSE` and upstream notice/source data are in `NOTICE`; this file covers external Go modules reported for the shipped client, its Go standard library, and a separately credited internal/ecdh implementation.
Go standard-library source text: [go1.24.5 LICENSE](https://go.googlesource.com/go/+/refs/tags/go1.24.5/LICENSE).
Complete license terms are stored once per SPDX identifier in `../third-party-licenses/`; entries below group components and retain their copyright/attribution notices without repeating license bodies.

## Apache-2.0

License text: `../third-party-licenses/Apache-2.0.txt`

Components: github.com/klauspost/compress.

- Copyright (c) 2012 The Go Authors. All rights reserved.
- Copyright (c) 2019 Klaus Post. All rights reserved.

## BSD-2-Clause

License text: `../third-party-licenses/BSD-2-Clause.txt`

Components: github.com/gorilla/websocket.

- Copyright (c) 2013 The Gorilla WebSocket Authors. All rights reserved.

## BSD-3-Clause

License text: `../third-party-licenses/BSD-3-Clause.txt`

Components: Cloak internal/ecdh (wsddn/go-ecdh), Go standard library (go1.24.5),
  github.com/klauspost/compress, github.com/klauspost/compress/internal/snapref,
  github.com/refraction-networking/utls, github.com/refraction-networking/utls/dicttls,
  golang.org/x/crypto, golang.org/x/sys.

- Copyright (c) 2009 The Go Authors. All rights reserved.
- Copyright (c) 2011 The Snappy-Go Authors. All rights reserved.
- Copyright (c) 2012 The Go Authors. All rights reserved.
- Copyright (c) 2014, tang0th.
- Copyright (c) 2019 Klaus Post. All rights reserved.
- Copyright (c) 2023, Gaukas Wang
- Copyright 2009 The Go Authors.

## LGPL-3.0

License text: `../third-party-licenses/LGPL-3.0.txt`

Components: github.com/juju/ratelimit.

## MIT

License text: `../third-party-licenses/MIT.txt`

Components: github.com/andybalholm/brotli, github.com/klauspost/compress,
  github.com/klauspost/compress/zstd/internal/xxhash, github.com/sirupsen/logrus.

- Copyright (c) 2009, 2010, 2013-2016 by the Brotli Authors.
- Copyright (c) 2012 The Go Authors. All rights reserved.
- Copyright (c) 2014 Simon Eskildsen
- Copyright (c) 2015 Klaus Post
- Copyright (c) 2016 Caleb Spare
- Copyright (c) 2019 Klaus Post. All rights reserved.
- Copyright 2016-2017 The New York Times Company

## Additional upstream notices

- Cloak `internal/ecdh` has a source-specific BSD-3-Clause condition 3 naming tang0th; see `../third-party-licenses/additional-notices/ck-client-ecdh-BSD-3-Clause-variation.txt`.
- The Go standard library and `golang.org/x/crypto` / `golang.org/x/sys` use the Google LLC BSD-3-Clause condition 3 variation; `klauspost/compress`, its `internal/snapref` package, and `refraction-networking/utls` use the Google Inc variation. Both clauses are preserved at `../third-party-licenses/additional-notices/Go-BSD-3-Clause-source-variations.txt`.
- `juju/ratelimit` adds a special static/dynamic linking exception to LGPL-3.0. The exception is reproduced separately at `../third-party-licenses/additional-notices/ck-client-ratelimit-linking-exception.txt`; read it together with the shared LGPL-3.0 text.
