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>

test/voice-packet.test.ts

@@ -0,0 +1,38 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { writeVarint, readVarint, encodeVoice, decodeVoice, relayAsServer } from '../src/core/voice-packet.ts';
+
+test('Mumble varints round trip at every size boundary', () => {
+  for (const v of [0, 1, 0x7f, 0x80, 0x3fff, 0x4000, 0x1fffff, 0x200000, 0xfffffff, 0x10000000, 0xffffffff, 0x100000000, 2 ** 40 + 5]) {
+    const out: number[] = [];
+    writeVarint(out, v);
+    assert.deepEqual(readVarint(new Uint8Array(out), 0), [v, out.length], `value ${v}`);
+  }
+  const small: number[] = [];
+  writeVarint(small, 300);
+  assert.deepEqual(small, [0x81, 0x2c], 'matches PacketDataStream encoding');
+});
+
+for (const protobuf of [false, true]) {
+  test(`${protobuf ? 'protobuf' : 'legacy'} voice packets survive a server relay`, () => {
+    const opus = new Uint8Array([0xfc, 1, 2, 3, 250]);
+    for (const last of [false, true]) {
+      const sent = encodeVoice({ target: 0, frame: 1234, opus, last }, protobuf);
+      const got = decodeVoice(relayAsServer(sent, 42, protobuf));
+      assert.deepEqual(got, { session: 42, target: 0, frame: 1234, opus, last });
+    }
+  });
+}
+
+test('legacy header layout: opus type, terminator bit in the size field', () => {
+  const p = encodeVoice({ target: 3, frame: 5, opus: new Uint8Array(10), last: true }, false);
+  assert.equal(p[0], (4 << 5) | 3);
+  assert.equal(p[1], 5);
+  assert.deepEqual([p[2], p[3]], [0x80 | 0x20, 10], 'size 10 | 0x2000 as a 2-byte varint');
+});
+
+test('non-audio packets are ignored', () => {
+  assert.equal(decodeVoice(new Uint8Array([1, 2, 3])), null, 'protobuf ping');
+  assert.equal(decodeVoice(new Uint8Array([0x20, 5])), null, 'legacy ping');
+  assert.equal(decodeVoice(new Uint8Array([0x80, 1])), null, 'truncated');
+});