agent: lumotia-rebrand — drop MagnotiaError prefix, now lumotia_core::Error

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>

crates/storage/src/error.rs

@@ -1,8 +1,8 @@
 //! Storage-local typed error.
 //!
 //! Backend code that wants to branch on storage failure modes pattern-matches
-//! on [`Error`] directly. The crate boundary into [`lumotia_core::error::MagnotiaError`]
-//! flattens this into a [`MagnotiaError::Storage`] variant carrying a serde-friendly
+//! on [`Error`] directly. The crate boundary into [`lumotia_core::error::Error`]
+//! flattens this into a [`Error::Storage`] variant carrying a serde-friendly
 //! `kind`, an `operation` label, and the Display output as `detail` — so the
 //! frontend (which still receives stringified errors from Tauri commands today)
 //! keeps working, and Area E can later expose the typed `kind` to the FE without
@@ -14,7 +14,7 @@
 use std::borrow::Cow;
 use std::path::PathBuf;
 
-use lumotia_core::error::{MagnotiaError, StorageKind};
+use lumotia_core::error::{Error as CoreError, StorageKind};
 
 /// Kinds of database-open operation that can fail before the pool is ready.
 #[derive(Debug, Clone, Copy)]
@@ -145,7 +145,7 @@ pub enum Error {
 }
 
 impl Error {
-    /// Discriminator for the boundary conversion into [`MagnotiaError`].
+    /// Discriminator for the boundary conversion into [`Error`].
     pub fn kind(&self) -> StorageKind {
         match self {
             Error::DatabaseOpen { .. } => StorageKind::DatabaseOpen,
@@ -157,7 +157,7 @@ impl Error {
         }
     }
 
-    /// Operation label that flows into the [`MagnotiaError::Storage`] boundary
+    /// Operation label that flows into the [`Error::Storage`] boundary
     /// shape. For per-query failures this is the caller-provided label;
     /// for the other variants it's the variant's intrinsic label.
     pub fn operation_label(&self) -> Cow<'static, str> {
@@ -175,14 +175,14 @@ impl Error {
 }
 
 /// Boundary conversion — flattens the typed error into the wire-friendly
-/// [`MagnotiaError::Storage`] variant. Lives in the storage crate (not in core)
+/// [`CoreError::Storage`] variant. Lives in the storage crate (not in core)
 /// to avoid a `core -> storage` dependency cycle.
-impl From<Error> for MagnotiaError {
+impl From<Error> for CoreError {
     fn from(error: Error) -> Self {
         let kind = error.kind();
         let operation = error.operation_label().into_owned();
         let detail = error.to_string();
-        MagnotiaError::Storage {
+        CoreError::Storage {
             kind,
             operation,
             detail,