chore: merge rename commit into Plan 1B branch

Resolves conflicts from merging origin/main (idfoto→relicario rename):
- Kept Plan 1A's typed-item vault.rs, lib.rs, integration.rs over main's
  old entry-based versions
- Took main's relicario_dir() fix in CLI main.rs (sed had missed idfoto_dir)
- Kept Plan 1A's UnsupportedFormatVersion error variant in crypto.rs
- Kept Plan 1A's opaque Decrypt message (audit M4) in error.rs
- Deleted entry.rs (replaced by item.rs + typed modules in Plan 1A)
- Resolved Cargo.toml description to main's "relicario password manager"

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/relicario-core/src/lib.rs

@@ -1,6 +1,6 @@
 //! # relicario-core
 //!
-//! Platform-agnostic core library for the idfoto password manager.
+//! Platform-agnostic core library for the relicario password manager.
 //!
 //! This crate is intentionally **bytes-in/bytes-out** -- it performs no filesystem
 //! access, no network I/O, and no git operations. All inputs arrive as byte slices