Function check 

pub fn check(config_dir: &Path) -> CheckReport

Parse ~/.config/fresh/init.ts via oxc and report syntax errors.

This is the “parse mode” from the design (§5.1): always-on, low-latency, catches the mistakes that would otherwise blow up at startup. The deeper type-check (tsc --noEmit) and the scope-discipline lints (init/unconditional-preference, init/unconditional-plugin-load) are deliberately not implemented here — they’re strict-mode concerns that can grow on top of this foundation.