Init ring buffers in start_mixer

app.py

@@ -304,6 +304,7 @@ def start_mixer():
         except Exception as e:
             return f"Failed to download model: {e}"
     # Launch mixer binary — it runs inference and outputs to stdout
+    init_ring_buffers()
     _mixer_proc = subprocess.Popen(
         [MIXER_BIN, MODEL_PATH, "-s", "2"],
         stdout=open(STATE_LOG, 'a'),