Feature suggestion: Add an "Insert" operation. #454
Description
Sometimes, when another activity is started during a timed activity, and then the inserted activity finishes and the user returns to the original activity, this inserted activity isn't recorded in the Simple Time Tracker. Adding this functionality usually requires gradually splitting or modifying the activity, which is cumbersome. It's recommended to add an "insert" operation that allows you to insert another activity into an activity (either one that has finished timing or one that is currently timing).