feat: implement event notification system

- Add core event notification interfaces
- Support multiple notification backends:
  - Webhook (default)
  - Kafka
  - MQTT
  - HTTP Producer
- Implement configurable event filtering
- Add async event dispatching with backpressure handling
- Provide serialization/deserialization for event payloads

This module enables system events to be published to various endpoints
with consistent delivery guarantees and failure handling.

crates/event-notifier/src/error.rs

@@ -1,25 +1,45 @@
-// src/error.rs
 use thiserror::Error;
+use tokio::sync::mpsc::error;
+use tokio::task::JoinError;
 
+/// The `Error` enum represents all possible errors that can occur in the application.
+/// It implements the `std::error::Error` trait and provides a way to convert various error types into a single error type.
 #[derive(Error, Debug)]
 pub enum Error {
-    #[error("target not found: {0}")]
-    TargetNotFound(String),
-
-    #[error("send failed: {0}")]
-    SendError(String),
-
-    #[error("target error: {0}")]
-    TargetError(String),
-
-    #[error("invalid configuration: {0}")]
+    #[error("Join error: {0}")]
+    JoinError(#[from] JoinError),
+    #[error("IO error: {0}")]
+    Io(#[from] std::io::Error),
+    #[error("Serialization error: {0}")]
+    Serde(#[from] serde_json::Error),
+    #[error("HTTP error: {0}")]
+    Http(#[from] reqwest::Error),
+    #[cfg(feature = "kafka")]
+    #[error("Kafka error: {0}")]
+    Kafka(#[from] rdkafka::error::KafkaError),
+    #[cfg(feature = "mqtt")]
+    #[error("MQTT error: {0}")]
+    Mqtt(#[from] rumqttc::ClientError),
+    #[error("Channel send error: {0}")]
+    ChannelSend(#[from] Box<error::SendError<crate::event::Event>>),
+    #[error("Feature disabled: {0}")]
+    FeatureDisabled(&'static str),
+    #[error("Event bus already started")]
+    EventBusStarted,
+    #[error("necessary fields are missing:{0}")]
+    MissingField(&'static str),
+    #[error("field verification failed:{0}")]
+    ValidationError(&'static str),
+    #[error("{0}")]
+    Custom(String),
+    #[error("Configuration error: {0}")]
     ConfigError(String),
-
-    #[error("store error: {0}")]
-    StoreError(String),
-
-    #[error("invalid event name: {0}")]
-    InvalidEventName(String), // 添加此变体
+    #[error("Configuration loading error: {0}")]
+    Figment(#[from] figment::Error),
 }
 
-pub type Result<T> = std::result::Result<T, Error>;
+impl Error {
+    pub(crate) fn custom(msg: &str) -> Error {
+        Self::Custom(msg.to_string())
+    }
+}