Feat/sloc initial sweep

[cryptanu]

Summary

• Add sloc-initial-sweep plugin for logical/physical SLOC counting with per-folder/per-language breakdowns.
• Include script, references, and examples under skills/sloc-initial-sweep/ in Trail of Bits plugin layout.
• Document usage and list the plugin in the root README under Code Auditing.

[CLAassistant]

All committers have signed the CLA.

[dguido]

Thanks for this @cryptanu! We actually have a very similar one internally :>. I will look into whether we want to open source it.

[cryptanu]

Thanks for this @cryptanu! We actually have a very similar one internally :>. I will look into whether we want to open source it.

It was a great first issue to get the hang of using these skills for me. Would like to have a look at what other primitives your internal tooling may cover that's not present here as well. Ty!

[dguido]

@cryptanu FYI I will look at this skill vs our internal one this week and consider what to do with it. Btw, the CLA lets us potentially include your contribution in our commercial tooling, which helps fund continued maintenance of our open source work. Please accept it and we'll keep working on these skills for everyone's benefit :).

[cryptanu]

Sure. I'm curious, do the other skills maintain context by internally flattening with Slither on every run. I have an idea to run a "flatten" skill and cache this for future runs. Do lmk if this could improve performance and lower token cost per run.