feat(tts): support multi-reference personalities

Saved profiles previously resolved to one audio path and transcript, so
cloning backends could not use several examples of one personality.

Store ordered audio and transcript pairs while preserving the legacy
first-reference fields. Fish Speech and audio.cpp receive all pairs,
including on distributed workers. Other backends retain their
single-reference behavior.

Assisted-by: Codex:gpt-5
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

backend/cpp/audio-cpp/generation_request.cpp

@@ -22,7 +22,8 @@ bool voice_is_reference_file(const std::string &voice) {
 
 RequestShape build_tts_shape(const backend::TTSRequest &request) {
     RequestShape shape;
-    shape.has_voice_reference = voice_is_reference_file(request.voice());
+    shape.has_voice_reference = voice_is_reference_file(request.voice()) ||
+                                request.params().find("multi_reference_cond") != request.params().end();
     // !empty() as well as has_instructions(), and it must match the guard in
     // build_tts_request: a request whose instructions are an empty string
     // carries no style condition, so telling routing to prefer VoiceDesign for