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>

src/lib/menu.svelte.ts

@@ -0,0 +1,25 @@
+export interface MenuItem {
+  label: string;
+  action?: () => void;
+  danger?: boolean;
+  checked?: boolean;
+  disabled?: boolean;
+  separator?: boolean;
+}
+
+// One context menu for the whole app, opened at the pointer position
+class MenuStore {
+  open = $state<{ x: number; y: number; items: MenuItem[] } | null>(null);
+
+  show(e: MouseEvent, items: MenuItem[]): void {
+    e.preventDefault();
+    e.stopPropagation();
+    this.open = { x: e.clientX, y: e.clientY, items };
+  }
+
+  close(): void {
+    this.open = null;
+  }
+}
+
+export const menu = new MenuStore();