VAD: Silero v5 (vad-web) statt RMS-Eigenbau — Turn-Ende 900 -> 450 ms (Review P1-7)

- useVAD.ts: MicVAD (neuronale Sprach- statt Pegel-Erkennung), redemptionMs 450,
  preSpeechPad 320 ms, WAV direkt aus Float32 (kein webm/Opus-Umweg mehr zur Box)
- boxStt.ts: Dateiname passend zum Blob-Typ (rec.wav | rec.webm)
- Assets self-hosted unter /vad/ via scripts/copy-vad-assets.mjs (npm postinstall), offlinefaehig
- Verifiziert: tsc + Build sauber, App startet, Assets werden ausgeliefert (Mikro-Test: User)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

client/lucy-desktop/electron.vite.config.ts

@@ -12,6 +12,9 @@ export default defineConfig({
   renderer: {
     root: resolve(__dirname, "src/renderer"),
     build: { rollupOptions: { input: { index: resolve(__dirname, "src/renderer/index.html") } } },
+    // Silero-VAD-Assets (Worklet + ONNX + onnxruntime-WASM) liegen self-hosted in
+    // src/renderer/public/vad/ (scripts/copy-vad-assets.mjs, läuft via npm postinstall) —
+    // Pfade = baseAssetPath/onnxWASMBasePath in useVAD.ts.
     plugins: [react()],
   },
 })