Home: Fix the mindset element to the top

Keep the mindset element always on the screen.
I'm not sure how I feel about the current
layout, but let's try it for a little bit.
Mindset: Add helper sentences

When mindsets are selected, add a helper
sentence to the top of the task list.

When hovering over a mindset, show the
name of it.
Fix: Tour: Plan: Moving tasks

We were mixing shared mutable state
with closures and events and it was
bad.