feat(tts): integrate autonomous Piper neural TTS with zero-latency pre-warming for words and context

.gitignore

@@ -14,6 +14,8 @@ ENV/
 *.db-wal
 *.db-shm
 data/ollama/
+data/piper/
+data/audio_cache/
 data/*.db
 data/*.db-wal
 data/*.db-shm