set correct fallback sequence

utils/tts_engines.py

@@ -370,6 +370,9 @@ def get_available_engines() -> List[str]:
     if DIA_AVAILABLE:
         available.append('dia')
     
+    if DIA_SPACE_AVAILABLE:
+        available.append('dia_space')
+    
     # Dummy is always available
     available.append('dummy')
     
@@ -380,7 +383,7 @@ def create_engine(engine_type: str, lang_code: str = 'z') -> TTSEngineBase:
     """Create a specific TTS engine
     
     Args:
-        engine_type (str): Type of engine to create ('kokoro', 'kokoro_space', 'dia', 'dummy')
+        engine_type (str): Type of engine to create ('kokoro', 'kokoro_space', 'dia', 'dia_space', 'dummy')
         lang_code (str): Language code for the engine
         
     Returns:
@@ -404,6 +407,11 @@ def create_engine(engine_type: str, lang_code: str = 'z') -> TTSEngineBase:
             raise ValueError("Dia TTS engine is not available")
         return DiaTTSEngine(lang_code)
     
+    elif engine_type == 'dia_space':
+        if not DIA_SPACE_AVAILABLE:
+            raise ValueError("Dia Space TTS engine is not available")
+        return DiaSpaceTTSEngine(lang_code)
+    
     elif engine_type == 'dummy':
         return DummyTTSEngine(lang_code)