Revert "feat: replace MeloTTS with Coqui XTTS-v2 natural Korean voice"

This reverts commit 39a0944105.

.env.example

@@ -34,23 +34,18 @@ WHISPER_DEVICE=cuda
 WHISPER_COMPUTE_TYPE=float16
 # Optional explicit Piper voice model (.onnx). If empty, the jarvis default is used.
 TTS_PIPER_MODEL_PATH=
-# TTS engine: "xtts" (default) uses the Coqui XTTS-v2 natural Korean voice
-# served by the warm xtts-worker. Set to "piper" to use the English Piper voice
-# directly. (MeloTTS was removed; "melo" only works with an out-of-band worker.)
-TTS_ENGINE=xtts
-# XTTS-v2 voice settings. Speaker is any built-in studio voice; "Ana Florence"
-# is a natural female voice. Language is the synthesis language (ko = Korean).
-XTTS_SPEAKER=Ana Florence
-XTTS_LANGUAGE=ko
-XTTS_DEVICE=cuda
-# Where the bridge reaches the in-container XTTS worker, and how long it waits
-# for a synthesis (XTTS is slower than Melo: ~1-2s/sentence on GPU).
-XTTS_WORKER_URL=http://127.0.0.1:8771
-XTTS_TIMEOUT=30
-# Neural-only by default: if XTTS synthesis fails the bridge returns no audio
+# TTS engine: "melo" (default) uses the MeloTTS Korean voice served by the warm
+# melo-worker (Korean speaker, speed 1.5). Set to "piper" to use Piper directly.
+TTS_ENGINE=melo
+# Melo-only by default: if MeloTTS synthesis fails the bridge returns no audio
 # rather than speaking Korean through the English Piper voice (which mangles it).
 # Set to 1 only if you explicitly want the Piper fallback.
-XTTS_FALLBACK_PIPER=0
+MELO_FALLBACK_PIPER=0
+# Where the bridge reaches the in-container MeloTTS worker, and how long it
+# waits for a synthesis. Speaking rate is set on the worker via MELO_SPEED.
+MELO_WORKER_URL=http://127.0.0.1:8770
+MELO_TIMEOUT=30
+MELO_SPEED=1.5
 
 # ---------------------------------------------------------------------------
 # Jarvis brain (Ollama-backed). In Docker these populate the rendered
@@ -231,7 +226,7 @@ COMPOSE_FILE=docker-compose.yml:docker-compose.gpu-linux.yml
 # OLLAMA_CHAT_MODEL=qwen2.5:7b   # quality (needs ~5GB VRAM + whisper small)
 # OLLAMA_CHAT_MODEL=qwen2.5:3b   # speed (fits easily, faster on 8GB GPUs)
 # WHISPER_MODEL=small            # small frees VRAM for a bigger LLM; medium=more accurate
-# XTTS_DEVICE=cuda               # cpu if no GPU on the bot host (XTTS is slow on CPU)
+# MELO_DEVICE=cuda               # cpu if no GPU on the bot host
 
 # --- Settings web UI (http://localhost:8765/settings on the bot host) ---
 # To reach it, expose the bridge to the host loopback: