Add Qwen3-TTS zero-shot voice cloning web UI

Extract the voice-cloning feature from jamiepine/voicebox (Qwen3-TTS Base
engine) into a small standalone app: FastAPI backend (engine.py + app.py)
wrapping create_voice_clone_prompt/generate_voice_clone, and a single-page
UI (upload or mic-record a reference clip + transcript -> synthesize any
text in that voice). Supports 10 languages incl. Korean; model loads lazily
and downloads on first use.

requirements.txt

@@ -0,0 +1,15 @@
+# voice_copy — zero-shot voice cloning UI (Qwen3-TTS)
+#
+# NOTE: install a torch build that matches your machine FIRST, e.g.
+#   CPU:            pip install torch
+#   NVIDIA (CUDA):  pip install torch --index-url https://download.pytorch.org/whl/cu128
+# then:  pip install -r requirements.txt
+
+qwen-tts>=0.1.1          # Qwen3-TTS model + generate_voice_clone (pulls transformers/accelerate/torchaudio/soundfile/librosa)
+fastapi>=0.109.0
+uvicorn[standard]>=0.27.0
+python-multipart>=0.0.6  # multipart form uploads
+soundfile>=0.12.0
+librosa>=0.10.0
+numpy>=1.24
+torch>=2.2.0             # keep the torch you installed above; listed so a bare install still works