Fix dashboard separation mode switch

platform/llama-dashboard/app.py

@@ -277,7 +277,7 @@ def router_status() -> tuple[dict[str, Any], str | None]:
 
 
 def change_mode(mode: str) -> tuple[int, dict[str, Any]]:
-    if mode not in {"llm", "music"}:
+    if mode not in {"llm", "music", "separation"}:
         return 400, {"error": "invalid mode"}
     headers = {"Accept": "application/json", "Content-Type": "application/json"}
     if ROUTER_API_KEY: