Update requirements.txt

requirements.txt

@@ -1,6 +1,10 @@
 # TTS engine
 coqui-tts>=0.22.0
 
+# transformers >=4.38 removed `isin_mps_friendly` which coqui-tts still
+# imports from transformers.pytorch_utils — pin to the last compatible release.
+transformers>=4.33.0,<4.38.0
+
 # Web framework
 fastapi>=0.111.0
 uvicorn[standard]>=0.29.0
@@ -8,4 +12,4 @@ python-multipart>=0.0.9
 
 # PyTorch CPU-only wheel (much smaller image, sufficient for inference)
 torch>=2.2.0
-torchaudio>=2.2.0
+torchaudio>=2.2.0