feat: rename crate from rustfs-event-notifier to rustfs-event

This change simplifies the crate name to better reflect its core functionality
as the event handling system for RustFS. The renamed package maintains all
existing functionality while improving naming consistency across the project.

- Updated all imports and references to use the new crate name
- Maintained API compatibility with existing implementations
- Updated tests to reflect the name change

crates/event/src/adapter/mqtt.rs

@@ -0,0 +1,58 @@
+use crate::ChannelAdapter;
+use crate::Error;
+use crate::Event;
+use crate::MqttConfig;
+use async_trait::async_trait;
+use rumqttc::{AsyncClient, MqttOptions, QoS};
+use std::time::Duration;
+use tokio::time::sleep;
+
+/// MQTT adapter for sending events to an MQTT broker.
+pub struct MqttAdapter {
+    client: AsyncClient,
+    topic: String,
+    max_retries: u32,
+}
+
+impl MqttAdapter {
+    /// Creates a new MQTT adapter.
+    pub fn new(config: &MqttConfig) -> (Self, rumqttc::EventLoop) {
+        let mqtt_options = MqttOptions::new(&config.client_id, &config.broker, config.port);
+        let (client, event_loop) = rumqttc::AsyncClient::new(mqtt_options, 10);
+        (
+            Self {
+                client,
+                topic: config.topic.clone(),
+                max_retries: config.max_retries,
+            },
+            event_loop,
+        )
+    }
+}
+
+#[async_trait]
+impl ChannelAdapter for MqttAdapter {
+    fn name(&self) -> String {
+        "mqtt".to_string()
+    }
+
+    async fn send(&self, event: &Event) -> Result<(), Error> {
+        let payload = serde_json::to_string(event).map_err(Error::Serde)?;
+        let mut attempt = 0;
+        loop {
+            match self
+                .client
+                .publish(&self.topic, QoS::AtLeastOnce, false, payload.clone())
+                .await
+            {
+                Ok(()) => return Ok(()),
+                Err(e) if attempt < self.max_retries => {
+                    attempt += 1;
+                    tracing::warn!("MQTT attempt {} failed: {}. Retrying...", attempt, e);
+                    sleep(Duration::from_secs(2u64.pow(attempt))).await;
+                }
+                Err(e) => return Err(Error::Mqtt(e)),
+            }
+        }
+    }
+}