Fix splice(-1,1) removing last user when logged-in user not found

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/stores/acctMgmt.ts

@@ -127,7 +127,9 @@ export const useAcctMgmtStore = defineStore('acctMgmtStore', {
       const loginStore = useLoginStore();
       const loginUserData:User = loginStore.userData;
       const foundLoginUserIndex = fetchedUserList.findIndex(user => user.username === loginUserData.username);
-      fetchedUserList.unshift(fetchedUserList.splice(foundLoginUserIndex, 1)[0]);
+      if (foundLoginUserIndex !== -1) {
+        fetchedUserList.unshift(fetchedUserList.splice(foundLoginUserIndex, 1)[0]);
+      }
       return fetchedUserList;
     },
     /**