Add logging

We should log e.g. events and potentially even the serialized nodes using a standard logging crate, i.e. either `log` or `tracing`.

Start by locating the framework's event handling and serialized-node paths, then compare how the standard `log` and `tracing` crates would fit. Decide what events and serialized nodes should be logged, and verify that the chosen integration produces useful output without disrupting the UI framework.

Written by the indexing model from the issue text.