Implement hysteresis for metric status changes to prevent flapping

Add comprehensive hysteresis support to prevent status oscillation near
threshold boundaries while maintaining responsive alerting.

Key Features:
- HysteresisThresholds with configurable upper/lower limits
- StatusTracker for per-metric status history
- Default gaps: CPU load 10%, memory 5%, disk temp 5°C

Updated Components:
- CPU load collector (5-minute average with hysteresis)
- Memory usage collector (percentage-based thresholds)
- Disk temperature collector (SMART data monitoring)
- All collectors updated to support StatusTracker interface

Cache Interval Adjustments:
- Service status: 60s → 10s (faster response)
- Disk usage: 300s → 60s (more frequent checks)
- Backup status: 900s → 60s (quicker updates)
- SMART data: moved to 600s tier (10 minutes)

Architecture:
- Individual metric status calculation in collectors
- Centralized StatusTracker in MetricCollectionManager
- Status aggregation preserved in dashboard widgets

agent/src/main.rs

@@ -1,14 +1,14 @@
 use anyhow::Result;
 use clap::Parser;
-use tracing::{info, error};
+use tracing::{error, info};
 use tracing_subscriber::EnvFilter;
 
 mod agent;
 mod cache;
-mod config;
-mod communication;
-mod metrics;
 mod collectors;
+mod communication;
+mod config;
+mod metrics;
 mod notifications;
 mod utils;
 
@@ -22,7 +22,7 @@ struct Cli {
     /// Increase logging verbosity (-v, -vv)
     #[arg(short, long, action = clap::ArgAction::Count)]
     verbose: u8,
-    
+
     /// Configuration file path
     #[arg(short, long)]
     config: Option<String>,
@@ -31,32 +31,32 @@ struct Cli {
 #[tokio::main]
 async fn main() -> Result<()> {
     let cli = Cli::parse();
-    
+
     // Setup logging
     let log_level = match cli.verbose {
         0 => "info",
-        1 => "debug", 
+        1 => "debug",
         _ => "trace",
     };
-    
+
     tracing_subscriber::fmt()
         .with_env_filter(EnvFilter::from_default_env().add_directive(log_level.parse()?))
         .init();
-    
+
     info!("CM Dashboard Agent starting with individual metrics architecture...");
-    
+
     // Create and run agent
     let mut agent = Agent::new(cli.config).await?;
-    
+
     // Setup graceful shutdown channel
     let (shutdown_tx, shutdown_rx) = tokio::sync::oneshot::channel();
-    
+
     let ctrl_c = async {
         tokio::signal::ctrl_c()
             .await
             .expect("failed to install Ctrl+C handler");
     };
-    
+
     // Run agent with graceful shutdown
     tokio::select! {
         result = agent.run(shutdown_rx) => {
@@ -72,7 +72,7 @@ async fn main() -> Result<()> {
             tokio::time::sleep(std::time::Duration::from_millis(100)).await;
         }
     }
-    
+
     info!("Agent shutdown complete");
     Ok(())
-}
+}