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/Cargo.toml

@@ -2,7 +2,7 @@
 name = "relicario-core"
 version = "0.1.0"
 edition = "2021"
-description = "Core library for idfoto password manager"
+description = "Core library for relicario password manager"
 
 [dependencies]
 thiserror = "2"
@@ -25,3 +25,4 @@ hex = "0.4"
 url = { version = "2", features = ["serde"] }
 getrandom = "0.2"
 
+[dev-dependencies]