Initial commit: mumh5, a modern Mumble client

Electron desktop app with a Svelte 5 interface for any Mumble server.

- Mumble protocol core: TLS, handshake, channels, users, text, plugin data,
  client-side pacing of Murmur's rate limits
- Voice: WebCodecs Opus over the TCP tunnel, voice activity, push to talk,
  always-on, devices, per-user volume and local mute
- Several servers at once, voice on one; server rail with icons and ordering
- Chat: channels, direct messages, side chat, file sharing through f0ckm,
  inline images without it, click-to-play YouTube
- Profiles with rich descriptions, registration, rename, nicknames,
  connection information and moderation menus
- Identity wizard, multiple identities, PKCS#12 import/export, desktop
  Mumble certificate import, certificate pinning and viewer
- Tray icon with voice state
- Unit, server and end-to-end tests against a real Murmur

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

THIRD_PARTY_NOTICES.md

@@ -0,0 +1,43 @@
+# Third-party notices
+
+## Mumble protocol definitions
+
+`proto/Mumble.proto` and `proto/MumbleUDP.proto` are copied from the Mumble project
+(https://github.com/mumble-voip/mumble). `src/core/mumble-pb.js` and `src/core/mumble-udp-pb.js`
+are generated from them. They are covered by the following license:
+
+```
+Copyright (C) The Mumble Developers
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+- Redistributions of source code must retain the above copyright notice,
+  this list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+- Neither the name of The Mumble Developers nor the names of its
+  contributors may be used to endorse or promote products derived from this
+  software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
+CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+```
+
+## npm dependencies
+
+Runtime and build dependencies (Electron, Svelte, protobufjs, node-forge, DOMPurify and
+others) are distributed under their own licenses, found in each package under `node_modules/`.