implement: src/concurrency -- rayon parallel stats over full season data

[BryanChasko]

topic: concurrency

rust's ownership model makes data-race-free concurrency a compile-time guarantee.
rayon adds effortless parallelism via par_iter().

concepts to demonstrate

• std::thread::spawn + join
• channels: mpsc::channel for inter-thread communication
• Arc<Mutex<T>> for shared mutable state
• rayon par_iter() for parallel data processing

patriots theme

parallel stat aggregation across all 2004 regular season games.
spawn a thread per week, compute weekly box scores, send results back via channel.
then rayon version: games.par_iter().map(compute_box_score).collect().

file

src/concurrency/parallel_stats.rs

note

rust-only concept. no python mirror. show how this compares to python's GIL limitations.