Add the browser version, a toolbar, description previews and hints

Browser version
- Self-hosted proxy (server/) that serves the web build and bridges WebSocket
  connections to Mumble servers over TLS, with a server allowlist or allow-any mode
- WebSocket transport and a browser platform layer; identities live in the browser
- npm run build:web, dev:web, proxy and test:e2e:web; proxy unit tests

Interface
- Toolbar next to mute and deafen: description editor, settings, expand or collapse all
- Channels with a description show a marker; resting on the row previews it
- Collapse all keeps channels with people open
- Hints (title tooltips) can be switched on in a new Accessibility settings tab
- New identities can set the username suggested when connecting
- Own user information tells the client address from the one the server sees

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

scripts/build-proxy.mjs

@@ -0,0 +1,15 @@
+import * as esbuild from 'esbuild';
+
+// Bundles the web proxy to one file, dist-proxy/proxy.mjs, that runs with plain Node.
+await esbuild.build({
+  entryPoints: { proxy: 'server/main.ts' },
+  outdir: 'dist-proxy',
+  outExtension: { '.js': '.mjs' },
+  bundle: true,
+  platform: 'node',
+  format: 'esm',
+  target: 'node22',
+  // Bundled CommonJS dependencies still call require()
+  banner: { js: "import { createRequire as __createRequire } from 'node:module'; const require = __createRequire(import.meta.url);" },
+  logLevel: 'info'
+});