Feature request: debug value flow like in Max

Right now Audion doesn't display any parameter values, nor any actual data flow.

At least for constant values of parameters, i.e. not modulated, it would perhaps not be too hard to display in the details pane on the left when a node is selected (on the right). But a "signal probe" like Max [does](https://docs.cycling74.com/legacy/max8/vignettes/signal_probe), in its debug mode, would be even more useful in Audion, although arguably that's more work.

Also, the "render capacity" % reported by Audion is very optimistic. In reality, one-core usage is about 10 times higher than reported in Audion, on a Zen 3 cpu at least.

No files, tests, or entry points are named. Start by locating the selected-node details pane and the render-capacity reporting, then define separately what constant parameter values, signal probing, and accurate CPU usage should display; done requires an agreed scope and validation for each behavior.

Written by the indexing model from the issue text.