implemented moving of items

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

frontend/src/routes/stock/Index.svelte

@@ -23,7 +23,7 @@
     let top_level = $state(null);
 
     async function move_dragged_to(new_loc){
-        const data = { item : draggedItem, target: new_loc };
+        const data = { item : draggedItem.id, target: new_loc.id };
         const url = api('stock/move_item');
         const res = await fetch(url,{
             credentials : 'include',
@@ -32,7 +32,10 @@
         });
         if (res.ok){
             yikes();
-        } else error(res);
+            location = new_loc;
+        } else {
+            error(res);
+        }
     }
 
     async function loadLocation(){