Build sqlswarm, a SQL database engine in Rust (standard library only; no crates can be added), so that it passes SQLite's sqllogictest suite. The grader calls Database::open() and Database::execute(sql) -> Result<Output, String> once per SQL statement, with the types from the slt crate: Value::{Null, Integer(i64), Real(f64), Text(String), Blob(Vec<u8>)} and Output::{Done, Rows(Vec<Vec<Value>>)}. Behaviour must match SQLite: type affinity, NULL handling, integer versus real arithmetic, and how results print (see slt/src/lib.rs, the grader). Engine code lives in src/; split it into modules such as lexer, parser, executor, storage and functions.