port logic to rust

[Asifdotexe]

1. Prioritize CPU-Bound Tasks First: The guide explicitly recommends starting with computationally intensive, CPU-bound tasks. The git
   blame calculations for thousands of files across thousands of commits is pure CPU grinding. Rust will chew through this, dropping our 20+
   hour runtime to a fraction of that time.
2. Strategy 3 (CLI Tools): The guide recommends CLI tools as the perfect entry point. We don't need to mess with complex FFI (PyO3) or
   microservices. We can simply build a self-contained Rust binary (theseus-cli) that reads the manifest.json, processes the Git repos
   using git2-rs, and spits out the final _graph.json files for the frontend.
3. Ecosystem Swaps: We will directly swap our Python libraries for the Rust equivalents mentioned:
   • Python's json module ➔ serde and serde_json (blazing fast serialization).
   • Python's argparse (or implicit script args) ➔ clap (clean command-line parsing).
   • Python's subprocess (shelling out to git) ➔ git2 crate (doing git blame completely in-memory with C-bindings).