Require consistent encodings on broadcast

[eggrobin]

This requires optimally picking encodings for each transmitter on the path, and explaining in the inspector how this limits connectivity.

See @DRVeyl’s comments on that last point:

You otherwise might end up with "this is the biggest set we made, and adding any other node resulted in a lower tech choice" and showing why a given missed node also fails at the chosen encoding choice?
Lower TL encoders being always less power-efficient per bit.