Remove myshell-openvoice from build — librosa==0.9.1 conflict

OpenVoice pins librosa==0.9.1; our stack needs librosa==0.10.2.
VoiceCloner degrades gracefully to base VITS voice when the package
is absent. Re-enable once OpenVoice supports librosa>=0.10.

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

requirements.txt

@@ -55,9 +55,11 @@ rapidfuzz==3.13.0
 # Speaker identification (ECAPA-TDNN 192-d embeddings, used by SpeakerProfileManager)
 speechbrain>=0.5.15
 
-# Voice cloning (OpenVoice V2 ToneColorConverter — installed at build time from GitHub)
-# HF Spaces blocks GitHub at *runtime* but allows it during Docker build via requirements.txt
-myshell-openvoice @ git+https://github.com/myshell-ai/OpenVoice.git
+# Voice cloning (OpenVoice V2 / myshell-openvoice) is NOT listed here.
+# myshell-openvoice pins librosa==0.9.1 which conflicts with our librosa==0.10.2.
+# VoiceCloner in src/tts/voice_cloner.py degrades gracefully (returns None) when
+# the package is absent — base VITS voice is used instead.
+# Re-enable once OpenVoice releases a version compatible with librosa>=0.10.
 
 # maliba-ai is NOT listed here — it has strict conflicting pins (librosa, soundfile).
 # It is installed lazily at runtime on first Bambara TTS call (see src/tts/waxal_tts.py).