Consider adding graph visualization utility for constraint graph

It's difficult to examine the algebraic graph built in the IR by just printing the nodes of the graph. So, some visualization utility would be useful to debug or examine the constraint graph while we don't have unit tests for IR. This utility could also be useful for users writing constraints in AirScript to visually examine the constraints finally produced.

There could be other ways to make life easier for contributors and users rather than graph visualization and should be explored more.

The issue mentions visualizing the algebraic constraint graph built in the IR. Start by examining the IR module to understand how the graph is represented. Look for existing debug printing of nodes. Research graph visualization libraries in Rust (e.g., `petgraph`). The utility should help debug constraints and be useful for AirScript users. 'Done' means a tool that can output a visual representation (like DOT format or an image) of the constraint graph.

Scritto dal modello di indicizzazione a partire dal testo della issue.