Shared error type for the hdl-cat workspace.

This crate defines a single [Error] enum used throughout every other hdl-cat-* crate. Each variant wraps an underlying concrete error from std, from comp-cat-rs, or from a domain context in hdl-cat.

Design

Error handling is explicit and hand-rolled — no thiserror, no anyhow, no silent panics. Every fallible operation in the workspace returns Result<T, Error>.

From impls are provided for every underlying error type so that ? propagates cleanly at every call site.