feat: add voice mode support via mic passthrough to container

Enables Claude Code's /voice command inside Docker containers by
capturing microphone audio in the Tauri webview and streaming it
into the container via a FIFO pipe.

Container: fake rec/arecord shims read PCM from a FIFO instead of
a real mic. Audio bridge exec writes PCM from Tauri into the FIFO.
Frontend: getUserMedia() + AudioWorklet captures 16kHz mono PCM
and streams it to the container via invoke("send_audio_data").
UI: "Mic Off/On" toggle button in the terminal view.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src/hooks/useVoice.ts

@@ -0,0 +1,98 @@
+import { useCallback, useRef, useState } from "react";
+import * as commands from "../lib/tauri-commands";
+
+type VoiceState = "inactive" | "starting" | "active" | "error";
+
+export function useVoice(sessionId: string) {
+  const [state, setState] = useState<VoiceState>("inactive");
+  const [error, setError] = useState<string | null>(null);
+
+  const audioContextRef = useRef<AudioContext | null>(null);
+  const streamRef = useRef<MediaStream | null>(null);
+  const workletRef = useRef<AudioWorkletNode | null>(null);
+
+  const start = useCallback(async () => {
+    if (state === "active" || state === "starting") return;
+    setState("starting");
+    setError(null);
+
+    try {
+      // 1. Start the audio bridge in the container (creates FIFO writer)
+      await commands.startAudioBridge(sessionId);
+
+      // 2. Get microphone access
+      const stream = await navigator.mediaDevices.getUserMedia({
+        audio: {
+          channelCount: 1,
+          echoCancellation: true,
+          noiseSuppression: true,
+          autoGainControl: true,
+        },
+      });
+      streamRef.current = stream;
+
+      // 3. Create AudioContext at 16kHz (browser handles resampling)
+      const audioContext = new AudioContext({ sampleRate: 16000 });
+      audioContextRef.current = audioContext;
+
+      // 4. Load AudioWorklet processor
+      await audioContext.audioWorklet.addModule("/audio-capture-processor.js");
+
+      // 5. Connect: mic → worklet → (silent) destination
+      const source = audioContext.createMediaStreamSource(stream);
+      const processor = new AudioWorkletNode(audioContext, "audio-capture-processor");
+      workletRef.current = processor;
+
+      // 6. Handle PCM chunks from the worklet
+      processor.port.onmessage = (event: MessageEvent<ArrayBuffer>) => {
+        const bytes = Array.from(new Uint8Array(event.data));
+        commands.sendAudioData(sessionId, bytes).catch(() => {
+          // Audio bridge may have been closed — ignore send errors
+        });
+      };
+
+      source.connect(processor);
+      processor.connect(audioContext.destination);
+
+      setState("active");
+    } catch (e) {
+      const msg = e instanceof Error ? e.message : String(e);
+      setError(msg);
+      setState("error");
+      // Clean up on failure
+      await commands.stopAudioBridge(sessionId).catch(() => {});
+    }
+  }, [sessionId, state]);
+
+  const stop = useCallback(async () => {
+    // Tear down audio pipeline
+    workletRef.current?.disconnect();
+    workletRef.current = null;
+
+    if (audioContextRef.current) {
+      await audioContextRef.current.close().catch(() => {});
+      audioContextRef.current = null;
+    }
+
+    if (streamRef.current) {
+      streamRef.current.getTracks().forEach((t) => t.stop());
+      streamRef.current = null;
+    }
+
+    // Stop the container-side audio bridge
+    await commands.stopAudioBridge(sessionId).catch(() => {});
+
+    setState("inactive");
+    setError(null);
+  }, [sessionId]);
+
+  const toggle = useCallback(async () => {
+    if (state === "active") {
+      await stop();
+    } else {
+      await start();
+    }
+  }, [state, start, stop]);
+
+  return { state, error, start, stop, toggle };
+}