Configuration loading and canonicalized hashing for lanekeep.

Loads lanekeep.config.ts or lanekeep.json, resolves the rule graph, and derives the hashes feeding the cache key.

How the config is read

A lanekeep.config.ts is a TypeScript module, so reading it means running it. A synthetic entry module imports the config's default export into a global, and a second evaluation hands back JSON.stringify of the parts that are data.

Going through JSON rather than reaching into engine values is deliberate. It keeps every value crossing the boundary plainly serializable, it makes the whole extraction one testable string, and it sidesteps threading engine lifetimes through this crate.

The one thing it cannot carry is a function, and check is a function. So the extraction separately records whether each rule has a callable check and reduce. Without that, a rule whose handler was misspelled would load cleanly and silently never fire — the worst failure this tool can have, because it looks exactly like passing.

A lanekeep.json is not a program, and is read as what it is: src/json.rs parses, validates and resolves it in Rust, and only a rule reference naming a TypeScript rule reaches the sandbox — because that rule's own declaration is the only place its id, query and card exist. The note above entry_source in this file records what that cost.