feat(auth): add authentication protocol definitions and build configuration

- Add TokenClaims message for JWT payload structure with user id, issuer, timestamps, and scopes
- Implement IssueTokenRequest/Response for creating access and refresh tokens with TTL support
- Create RefreshTokenRequest/Response for token rotation functionality
- Define RevokeTokenRequest/Response with support for single token or user-wide revocation
- Add VerifyTokenRequest/Response for validating JWT tokens with detailed claims information
- Implement signing key distribution system with GetSigningKeysRequest/Response
- Create TokenService gRPC service with IssueToken, RefreshToken, RevokeToken, VerifyToken, and GetSigningKeys methods
- Add build.rs configuration to compile proto files using tonic_prost_build
- Include channel, channel_settings, member, and permission protocol definitions for IM services
- Generate Rust code bindings through pb/core.rs and pb/im.rs modules

socket/message_bus/mod.rs

@@ -0,0 +1,31 @@
+pub mod redis;
+pub mod nats;
+
+use async_trait::async_trait;
+use thiserror::Error;
+use tokio::sync::mpsc;
+
+#[derive(Error, Debug)]
+pub enum MessageBusError {
+    #[error("Redis error: {0}")]
+    Redis(String),
+    #[error("NATS error: {0}")]
+    Nats(String),
+    #[error("Connection closed")]
+    ConnectionClosed,
+    #[error("Channel not found: {0}")]
+    ChannelNotFound(String),
+    #[error("Serialization error: {0}")]
+    Serialization(String),
+}
+
+#[async_trait]
+pub trait MessageBus: Send + Sync + 'static {
+    async fn publish(&self, channel: &str, message: &[u8]) -> Result<(), MessageBusError>;
+    async fn subscribe(&self, channel: &str) -> Result<mpsc::Receiver<Vec<u8>>, MessageBusError>;
+    async fn unsubscribe(&self, channel: &str) -> Result<(), MessageBusError>;
+    async fn close(&self) -> Result<(), MessageBusError>;
+}
+
+pub use redis::RedisMessageBus;
+pub use nats::NatsMessageBus;