refactor: 使用 @picovoice/web-voice-processor 替换手写音频采集管线

- 引入 WebVoiceProcessor 处理 getUserMedia、AudioContext 生命周期和 WASM 重采样
- 删除自定义 AudioWorklet (audio-processor.ts) 和线性插值重采样器 (resample.ts)
- 改善音频采集稳定性：自动检测 AudioContext suspended/closed 状态并重建
- 更精确的错误提示：区分权限拒绝、设备未找到、设备异常

AGENTS.md

@@ -84,17 +84,12 @@ web/
       app-store.ts           # Zustand store: connection, recording, preview, history, toast
     hooks/
       useWebSocket.ts        # WS client hook: connect, reconnect, message dispatch
-      useRecorder.ts         # Audio pipeline hook: getUserMedia, AudioWorklet, resample
+      useRecorder.ts         # Audio pipeline hook: WebVoiceProcessor (16kHz Int16 PCM capture)
     components/
       StatusBadge.tsx         # Connection status indicator
       PreviewBox.tsx          # Real-time transcription preview
       MicButton.tsx           # Push-to-talk button with animations
       HistoryList.tsx         # Transcription history with re-send
-      Toast.tsx               # Auto-dismiss toast notifications
-    lib/
-      resample.ts             # Linear interpolation resampler (native rate → 16kHz Int16)
-    workers/
-      audio-processor.ts      # AudioWorklet: PCM capture, 200ms frame accumulation
 ```
 
 ## Code Style — Go
@@ -158,8 +153,8 @@ Per-connection loggers via `slog.With("remote", addr)`.
 - Custom hooks for imperative APIs: `useWebSocket`, `useRecorder`
 - Zustand `getState()` in hooks/callbacks to avoid stale closures
 - Pointer Events for touch/mouse (not touch + mouse separately)
-- AudioWorklet for audio capture (not MediaRecorder)
-- `?worker&url` Vite import for AudioWorklet files
+- @picovoice/web-voice-processor for audio capture (16kHz Int16 PCM, WASM resampling)
+- WebVoiceProcessor handles getUserMedia, AudioContext lifecycle, cross-browser compat
 - WebSocket: binary for audio frames, JSON text for control messages
 - Tailwind CSS v4 with `@theme` design tokens; minimal custom CSS (keyframes only)