feat: import Chinese-localized Buzz source snapshot

Signed-off-by: cls_宁波本机 <908705107@qq.com>

crates/buzz-core/src/pairing/mod.rs

@@ -0,0 +1,80 @@
+//! NIP-AB device pairing — crypto primitives, message types, and error types.
+//!
+//! NIP-AB enables two Nostr devices to securely exchange a secret (e.g., an
+//! `nsec` or a NIP-46 bunker connection string) over an untrusted relay, using:
+//!
+//! 1. **HKDF-SHA256** for all key derivation (session ID, SAS code, transcript hash).
+//! 2. **ECDH** (via [`nostr::util::generate_shared_key`]) for the shared secret.
+//! 3. **NIP-44 v2** for encrypting the message payloads.
+//! 4. **Short Authentication String (SAS)** for out-of-band confirmation.
+//!
+//! # Module layout
+//!
+//! | Module | Contents |
+//! |--------|----------|
+//! | [`crypto`] | Pure HKDF derivation functions |
+//! | [`types`]  | Serde-serializable pairing message types |
+//!
+//! # Error handling
+//!
+//! All fallible operations in the pairing flow return [`PairingError`].
+
+pub mod crypto;
+pub mod qr;
+pub mod session;
+pub mod types;
+
+pub use qr::QrPayload;
+pub use session::{PairingSession, Role, SessionState};
+pub use types::{AbortReason, PairingMessage, PayloadType};
+
+use thiserror::Error;
+
+/// Errors that can occur during a NIP-AB pairing session.
+#[derive(Debug, Error)]
+pub enum PairingError {
+    /// The scanned QR URI was not a valid NIP-AB pairing URI.
+    #[error("invalid QR URI: {0}")]
+    InvalidQr(String),
+
+    /// The session ID extracted from a message was not a valid 32-byte hex string.
+    #[error("invalid session ID")]
+    InvalidSessionId,
+
+    /// The SAS code shown on both devices did not match — session must be aborted.
+    #[error("SAS mismatch")]
+    SasMismatch,
+
+    /// The transcript hash received from the peer did not match the locally computed value.
+    #[error("transcript hash mismatch")]
+    TranscriptMismatch,
+
+    /// A message arrived out of sequence or with the wrong type for the current state.
+    #[error("unexpected message type: expected {expected}, got {got}")]
+    UnexpectedMessage {
+        /// The message type that was expected at this point in the protocol.
+        expected: String,
+        /// The message type that was actually received.
+        got: String,
+    },
+
+    /// The pairing session exceeded its time limit without completing.
+    #[error("session expired")]
+    SessionExpired,
+
+    /// NIP-44 encryption or decryption failed.
+    #[error("NIP-44 error: {0}")]
+    Nip44(#[from] nostr::nips::nip44::Error),
+
+    /// JSON serialization or deserialization failed.
+    #[error("JSON error: {0}")]
+    Json(#[from] serde_json::Error),
+
+    /// A public key string could not be parsed.
+    #[error("invalid pubkey: {0}")]
+    InvalidPubkey(String),
+
+    /// Event signing or construction failed.
+    #[error("event signing failed: {0}")]
+    SigningError(String),
+}