pub fn append_convergence(
tasks_path: &Path,
expected_file_hash: &str,
items: &[String],
) -> Result<Vec<String>, String>Expand description
Appends a ## Phase N: Convergence section with one open task per item
to the tasks.md at tasks_path — the engine’s other sanctioned write
(Spec Kit’s converge append contract).
The file must still hash to expected_file_hash; IDs continue after the
highest existing one, the phase number after the highest existing phase.
The old bytes stay an exact prefix and every existing task re-parses
unchanged. No items → the file is not touched. Returns the new IDs.