debug: add exception logging to preferences save endpoint

dashboard/backend/routers/auth.py

@@ -378,13 +378,21 @@ async def get_preferences(current_user = Depends(auth.get_current_user)):
 
 @router.put("/preferences")
 async def save_preferences(request: Request, current_user = Depends(auth.get_current_user)):
+    import traceback
     from rbac import save_sidebar_order
+    try:
         body = await request.json()
         order = body.get("sidebar_order")
         if order is None or not isinstance(order, dict):
             raise HTTPException(status_code=400, detail="Missing sidebar_order dict")
         save_sidebar_order(current_user.username, order)
         return {"ok": True}
+    except HTTPException:
+        raise
+    except Exception as e:
+        print(f"Error saving preferences: {e}")
+        traceback.print_exc()
+        raise HTTPException(status_code=500, detail=str(e))
 
 @router.delete("/rbac/overrides/{username}")
 async def rbac_delete_override(username: str, current_user = Depends(auth.get_current_user)):