Expand description
Foundation crate shared across nils-* CLIs.
Each public module documents its own surface; crates/nils-common/README.md carries the
per-module narrative and the consumer index, and
docs/specs/workspace-shared-crate-boundary-v1.md carries the boundary contract.
§Compatibility rules
- Returns structured results only; user-facing warning/error text stays in caller adapters.
- Exit-code mapping stays in caller crates.
- APIs stay domain-neutral and must not encode crate-specific UX policies.
- Quoting and ANSI differences are expressed via explicit mode/policy parameters.