//! Core layer — the reusable, frontend-agnostic heart of Svault.
//!
//! Everything here is self-contained: crypto, vault storage, the policy engine,
//! the AI judge, metadata, keyring/master-key management, recovery, audit, and
//! the supporting file/session primitives. No module in `core` depends on a
//! frontend (`cli`, `tui`, `daemon`, `mcp`, `gui`) — frontends drive core, not
//! the other way around.