pub fn plan(old: &Catalog, new: &Catalog) -> Result<Vec<MigrationStep>>Expand description
The engine for non-module callers: diff two catalogs and return the ordered steps. Every step is the unmoduled base, so module affinity degenerates to a deterministic topological sort.
Every command’s migration plan comes from here — apply, diff, migrate new/update/validate/diff, baseline rendering, and validation all diff two managed catalogs through this one path.