implement: src/file_io -- std::fs reading CSV, serde for JSON

[BryanChasko]

topic: file i/o

reading and writing files, parsing structured data.

concepts to demonstrate

• std::fs::read_to_string, File::open
• BufReader for line-by-line reading
• csv crate for typed CSV deserialization into structs
• serde_json for reading/writing JSON
• proper error propagation with ? and anyhow

patriots theme

read datasets/roster_2004.csv into a Vec<Player>.
write a filtered stats summary to output/rushing_leaders.json.

files

src/file_io/read_roster.rs
src/file_io/write_summary.rs

reference

python mirror: basic_example_working_with_files_players.py