pub fn validate_id(id: &str) -> Result<()>Expand description
Validate that a task ID is safe for use in file paths.
IDs must match bl-[0-9a-fA-F]+. generate_id only ever emits
lowercase hex, but the loader accepts uppercase or mixed case so
a future bl that changes its generator does not break older
clients reading the same repo. The bl- prefix itself is
deliberately strict: mixing bl- and BL- in one repo would
fragment task filenames, so we surface that as a hard error.