Feature: error reporting with clean stacktraces

Right now, if the app panics, the stacktrace we see is very much messed up and hard to read, since the terminal is in "raw mode". It would be nice if we could catch all these errors, clear the terminal, exit raw mode and then print them to the screen.

Start by reproducing an app panic while the terminal is in raw mode, then trace how terminal setup and shutdown are handled. Add panic reporting that clears the terminal, exits raw mode, and prints a readable stacktrace; verify the terminal is restored after an error.

Written by the indexing model from the issue text.