feat(voice): first-class voice input and local TTS across web, desktop, and mobile (#2018)

Complete rebuild of voice input on a server-authoritative streaming
architecture, replacing the legacy Web Speech / whole-blob / WASM engines
and the dead voice-agent layer (~4k lines removed).

Speech-to-text (dictation):
- Client streams 16 kHz mono PCM16 chunks over /api/dictation/ws with
  seq/ack ordering; buffered audio is retained and replayed on reconnect
- Server transcribes and streams live partial transcripts back;
  segments auto-commit every ~15s with silence suppression and adaptive
  finalization timeouts
- Local provider (default, zero config): sherpa-onnx models in a forked
  worker process — auto-download with progress, staged extraction with
  verification, corrupt-model auto-recovery, idle shutdown after 5 min
- Model catalog with settings picker (accuracy/speed ratings, sizes,
  download/delete): Parakeet TDT v2 (English) and v3 (25 European
  languages, auto-detected), Whisper base and tiny (multilingual, light)
- OpenAI-compatible provider for any Whisper endpoint
- Composer overlay with live transcript, volume meter, timer, and
  cancel / insert / insert-and-send actions; failed transcriptions keep
  their audio for retry or accepting the partial text as-is
- Configurable keyboard shortcut (default mod+alt+v) toggles dictation;
  Enter confirms and Escape cancels while recording
- Overlay is pixel-aligned with the composer (measured footer height,
  matching paddings/typography/gaps) — no layout shift when toggling

Text-to-speech:
- Local Kokoro provider (English, 11 voices) synthesized in the same
  worker via /api/dictation/tts/speak, managed by the shared model
  pipeline; sentence-pipelined playback keeps time-to-first-audio at
  ~1 sentence regardless of message length, and stop cancels in-flight
  synthesis
- Sanitizer keeps inline-code content (strips backticks only), reads
  interword slashes aloud, and removes only absolute file paths

Settings:
- Voice page unified: a single read-aloud toggle owns all playback
  options (the confusing "Enable Voice Mode" is gone); a new "Enable
  voice input" toggle (default on, persisted to settings.json) hides
  the composer mic entirely when disabled

Mobile and transport:
- iOS/Android microphone permissions added (dictation was previously
  impossible on mobile)
- Fixed Android WebSocket upgrades: the Capacitor WebView origin
  (https://localhost) was missing from the packaged-client allowlist,
  403-ing every WS connection — root cause of the old mobile SSE lock,
  which is now removed for all transports

Security and conventions:
- All HTTP routes sit behind the global /api auth gate; the WS upgrade
  explicitly validates the UI session and origin, with oc_url_token
  narrowly allowlisted and covered by tests; the dictation socket mints
  a fresh URL token before connecting
- Routes register before the generic OpenCode proxy; the client goes
  through runtimeFetch/getRuntimeUrlResolver, and runtime switches
  reset the dictation socket
- VS Code deliberately reports dictation as unavailable (no server
  process in that runtime)

CI: workflow Node bumped 20 -> 22 to match the repo engines and fix
better-sqlite3 installs broken by node-gyp@latest on Node 20.

New dependency: sherpa-onnx-node (prebuilt N-API; macOS/Linux x64+arm64,
Windows x64 — Windows-on-ARM falls back to the OpenAI-compatible provider)

packages/web/server/lib/ui-auth/ui-auth.js

@@ -310,6 +310,7 @@ const isUrlAuthWebSocketPath = (pathname) => {
     || pathname === '/api/global/event/ws'
     || pathname === '/api/openchamber/realtime-proxy/ws'
     || pathname === '/api/terminal/ws'
+    || pathname === '/api/dictation/ws'
     || pathname.startsWith('/api/preview/proxy/');
 };
 

packages/web/server/lib/ui-auth/ui-auth.test.js

@@ -213,6 +213,28 @@ describe('ui auth client credential seam', () => {
     });
     expect(mountedServeCalled).toBe(true);
 
+    const dictationWsReq = {
+      method: 'GET',
+      path: '/api/dictation/ws',
+      url: `/api/dictation/ws?oc_url_token=${encodeURIComponent(urlToken)}`,
+      headers: { upgrade: 'websocket' },
+    };
+    expect(await auth.ensureSessionToken(dictationWsReq, null)).toBe('client:device-1');
+
+    const dictationHttpReq = {
+      method: 'GET',
+      path: '/api/dictation/ws',
+      url: `/api/dictation/ws?oc_url_token=${encodeURIComponent(urlToken)}`,
+      headers: { accept: 'application/json' },
+    };
+    const dictationHttpRes = createResponse();
+    let dictationHttpCalled = false;
+    await auth.requireAuth(dictationHttpReq, dictationHttpRes, () => {
+      dictationHttpCalled = true;
+    });
+    expect(dictationHttpCalled).toBe(false);
+    expect(dictationHttpRes.statusCode).toBe(401);
+
     const arbitraryGetReq = { method: 'GET', path: '/api/config/settings', url: `/api/config/settings?oc_url_token=${encodeURIComponent(urlToken)}`, headers: { accept: 'application/json' } };
     const arbitraryGetRes = createResponse();
     let arbitraryGetCalled = false;