pub fn probe(entry: &str, cmd_dir: &Path) -> Result<Schema, String>Expand description
Probe a binary for its schema by running <entry> --fdl-schema via the
shell and parsing stdout as JSON.
The entry is run with cwd = cmd_dir so relative paths (e.g. in
cargo run contexts) resolve correctly. On failure returns a string
error rather than panicking — callers almost always want to fall back.