Phase 3 of the rebrand cascade per locked decision D4. MagnotiaError -> Error in crates/core/src/error.rs (the crate name already qualifies it). 92 usages across 14 .rs files renamed via word-boundary sed. One collision required disambiguation: lumotia_storage already had its own local Error type (introduced by the slop-pass Area A residuals work). crates/storage/src/error.rs aliases the imported core error as CoreError on import; the From<Error> for CoreError boundary impl and the CoreError::Storage construction site use the alias. cargo build --workspace passes. cargo test --workspace: 330 pass, 0 fail. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>