chore: rename project from idfoto to relicario

Sweeping rename across crates, CLI binary, WASM bindings, extension, docs,
and vault metadata paths. Git remote updated to relicario.git.

- crates/idfoto-{core,cli,wasm} -> crates/relicario-{core,cli,wasm}
- IdfotoError -> RelicarioError
- IDFOTO_IMAGE env var -> RELICARIO_IMAGE
- ~/.config/idfoto -> ~/.config/relicario
- .idfoto/ vault metadata dir -> .relicario/ (breaking; pre-release)
- Binary name idfoto -> relicario
- Extension wasm module idfoto_wasm -> relicario_wasm
- Storage key idfotoSettings -> relicarioSettings
- All doc filenames and content references updated

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

crates/relicario-core/src/lib.rs

@@ -0,0 +1,47 @@
+//! # relicario-core
+//!
+//! 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
+//! or typed structs, and all outputs are returned as byte vectors or typed structs.
+//! This design makes the crate portable to WASM, Android (via JNI/UniFFI), and iOS
+//! without any conditional compilation or platform shims.
+//!
+//! ## Modules
+//!
+//! - [`error`] -- The unified error type ([`RelicarioError`]) used across the crate.
+//! - [`crypto`] -- Argon2id key derivation and XChaCha20-Poly1305 authenticated
+//!   encryption. This is the low-level "encrypt bytes / decrypt bytes" layer.
+//! - [`entry`] -- The vault data model: [`Entry`] (full credential),
+//!   [`ManifestEntry`] (searchable index metadata), and [`Manifest`] (the entry
+//!   index that lets you list/search without decrypting every entry).
+//! - [`vault`] -- Typed wrappers around [`crypto`] that serialize structs to JSON
+//!   before encrypting, and deserialize after decrypting.
+//! - [`imgsecret`] -- DCT-based steganography for embedding and extracting a
+//!   256-bit secret in a JPEG image. This is the novel component that provides the
+//!   second authentication factor.
+//!
+//! ## Crypto pipeline
+//!
+//! ```text
+//! passphrase (UTF-8 bytes) || image_secret (32 bytes from reference JPEG)
+//!   -> Argon2id(salt=vault_salt, m=64MiB, t=3, p=4)
+//!   -> master_key (32 bytes)
+//!   -> XChaCha20-Poly1305(nonce=random 24 bytes)
+//!   -> encrypted entry/manifest
+//! ```
+
+pub mod error;
+pub use error::{RelicarioError, Result};
+
+pub mod crypto;
+pub use crypto::{decrypt, derive_master_key, encrypt, KdfParams};
+
+pub mod entry;
+pub use entry::{generate_entry_id, Entry, Manifest, ManifestEntry};
+
+pub mod vault;
+pub use vault::{decrypt_entry, decrypt_manifest, encrypt_entry, encrypt_manifest};
+
+pub mod imgsecret;