Add text-to-speech via Piper TTS

Send text message → Piper TTS → WAV → OGG Opus → voice reply.

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

k8s/transcribator.yaml

@@ -40,6 +40,8 @@ spec:
               value: "http://whisper.whisper.svc:8000"
             - name: WHISPER_LANGUAGE
               value: "ru"
+            - name: PIPER_URL
+              value: "http://piper.piper.svc:5000"
           resources:
             requests:
               memory: "32Mi"