Reduce thread pool workers from 4 to 2 for 2-core optimization

app.py

@@ -310,7 +310,7 @@ async def generate_audio(text: str, voice: str = 'af_heart', speed: float = 1.0,
     start_time = time.time()
     
     loop = asyncio.get_event_loop()
-    max_parallel = min(len(chunks), 4)
+    max_parallel = min(len(chunks), 2)
     with ThreadPoolExecutor(max_workers=max_parallel) as executor:
         tasks = []
         for i, chunk in enumerate(chunks):
@@ -584,7 +584,7 @@ async def generate_cloned_audio(text: str, voice_sample_base64: str, speed: floa
         logger.info(f"Split text into {len(chunks)} chunks for voice cloning")
         
         loop = asyncio.get_event_loop()
-        max_parallel = min(len(chunks), 4)
+        max_parallel = min(len(chunks), 2)
         
         with ThreadPoolExecutor(max_workers=max_parallel) as executor:
             tasks = []