agent: lumotia-rebrand — rust workspace crates magnotia-* -> lumotia-*

Phase 2 of the rebrand cascade. Renames all 9 workspace crates from
magnotia-* to lumotia-* plus the src-tauri binary crate name:

- magnotia-ai-formatting   -> lumotia-ai-formatting
- magnotia-audio           -> lumotia-audio
- magnotia-cloud-providers -> lumotia-cloud-providers
- magnotia-core            -> lumotia-core
- magnotia-hotkey          -> lumotia-hotkey
- magnotia-llm             -> lumotia-llm
- magnotia-mcp             -> lumotia-mcp
- magnotia-storage         -> lumotia-storage
- magnotia-transcription   -> lumotia-transcription
- magnotia                 -> lumotia (src-tauri binary)
- magnotia_lib             -> lumotia_lib (src-tauri lib target)

Crate directories (crates/audio/ etc.) stay as-is; only the Cargo.toml
[package] name field changes plus all consumer module imports
(magnotia_core -> lumotia_core, etc.).

Remaining magnotia_* references at this point are intentional and
scoped to later phases: tracing targets (Phase 4), DB setting keys
magnotia_preferences/magnotia_history (Phase 5).

cargo build --workspace passes. cargo test --workspace: 330 pass, 0 fail.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/transcription/build.rs

@@ -11,7 +11,7 @@
 //! workspace ever pulls `tokenizers` into the dependency graph on a
 //! Windows target. If we ever legitimately need it we can reintroduce
 //! it via a sidecar (isolated process, separate CRT) rather than
-//! linking it into `magnotia_lib`.
+//! linking it into `lumotia_lib`.
 //!
 //! The check is advisory on non-Windows targets — it still prints a
 //! cargo:warning if `tokenizers` appears, so the Windows failure isn't