chore: improved proptest logging

For the Aspect property tests, make some changes to make it easier
to see what's going on:

- Instead of just a visit log, keep a log of all actions: adding
  constructs, adding aspects, and visiting are now all part of the
  same time sequence with time steps so it's easier to reason about.
- Clearly mark timed steps with `t=0`, `t=1`, etc.