Add auxiliary monitor configuration and enhance trigger logic for KVM switching

app/main.py

@@ -19,6 +19,7 @@ INDEX_PATH = STATIC_DIR / "index.html"
 
 class SettingsPayload(BaseModel):
     device_port: str
+    auxiliary_monitor_id: str | None = None
 
 
 def create_app(
@@ -59,6 +60,7 @@ def create_app(
         try:
             return active_service.save_settings(
                 device_port=payload.device_port,
+                auxiliary_monitor_id=payload.auxiliary_monitor_id,
             )
         except ValueError as exc:
             raise HTTPException(status_code=400, detail=str(exc)) from exc