Love the idea and giving it a shot.
My biggest initial recommendation is this:
"Give breaks" is broken as implemented. As somebody who uses pomodoro: a task is 4 hours or 8 pomodoro sessions; it's an estimate that includes my breaks. Don't make me do the math and don't make me have weird 2 number estimates for no reason.
e.g. If a plan is about 4 hours I need to enter 4 hours - 8 x 5 breaks or 3 hours and 20 minutes. Estimates of 3h20m seem really exact when it's really how you represent "about 4 hours" in your app.
If I start the plan and realize it's really going to be more like 6 hours I have to do that all over again and change two numbers again.
Other issues:
1) Same as the OC. e.g. changed all the times on the hours per day but didn't click any of the dones, 7 changes lost. UX principle: don't require confirmation on easy to correct changes.
2) No keyboard navigation.
3) I have to double or triple click all the time. e.g. change name of "untitled plan" is 3 clicks. Change number of hours in a plan 2 clicks