Create a dependency graph for the terminal

[r4gus]

The function fetchPackageDependencies() returns a map with values of type PackageInfo. Every package info contains references to other PackageInfo instances in the form of fingerprints, i.e. we have a flat data structure the resembles a (circular) dependency graph.

Having a function that generates a graph for the terminal serves at least two purposes:

• Create a complete graph as the result of calling zat --graph, e.g., zat --graph --terminal.
• Create a tree for a single package leaf that is part of the output when running zat --audit

zat audit example:

~/Dev/PassKeeZ$ zat --audit
Scanning build.zig.zon for vulnerabilities (8 package dependencies)

Package:      zbor
Version:      0.17.0
Title:        This is the first advisory published to zig-sec/advisory-db.
Date:         2025-03-16
ID:           ZIGSEC-2025-0001
Solution:     Don't worry! But you should upgrade anyway as a new zbor release is available.
Dependency tree:                                 <
keylib 0.6.1                                           < THIS IS NEW!
└── zbor 0.17.0                               <

error: 1 vulnerability found!

[r4gus]

The commit 2c0a4ce added a dependency tree to the output of the --audit command.