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/config/loader.rs

@@ -1,18 +1,19 @@
-use anyhow::{Context, Result};
-use std::path::Path;
-use std::fs;
 use crate::config::AgentConfig;
+use anyhow::{Context, Result};
+use std::fs;
+use std::path::Path;
 
 pub fn load_config<P: AsRef<Path>>(path: P) -> Result<AgentConfig> {
     let path = path.as_ref();
     let content = fs::read_to_string(path)
         .with_context(|| format!("Failed to read config file: {}", path.display()))?;
-    
+
     let config: AgentConfig = toml::from_str(&content)
         .with_context(|| format!("Failed to parse config file: {}", path.display()))?;
-    
-    config.validate()
+
+    config
+        .validate()
         .with_context(|| format!("Invalid configuration in file: {}", path.display()))?;
-    
+
     Ok(config)
-}
+}

agent/src/config/mod.rs

@@ -1,6 +1,5 @@
 use anyhow::Result;
 use cm_dashboard_shared::CacheConfig;
-use gethostname::gethostname;
 use serde::{Deserialize, Serialize};
 use std::path::Path;
 

agent/src/config/validation.rs

@@ -1,114 +1,126 @@
-use anyhow::{bail, Result};
 use crate::config::AgentConfig;
+use anyhow::{bail, Result};
 
 pub fn validate_config(config: &AgentConfig) -> Result<()> {
     // Validate ZMQ configuration
     if config.zmq.publisher_port == 0 {
         bail!("ZMQ publisher port cannot be 0");
     }
-    
+
     if config.zmq.command_port == 0 {
         bail!("ZMQ command port cannot be 0");
     }
-    
+
     if config.zmq.publisher_port == config.zmq.command_port {
         bail!("ZMQ publisher and command ports cannot be the same");
     }
-    
+
     if config.zmq.bind_address.is_empty() {
         bail!("ZMQ bind address cannot be empty");
     }
-    
+
     if config.zmq.timeout_ms == 0 {
         bail!("ZMQ timeout cannot be 0");
     }
-    
+
     // Validate collection interval
     if config.collection_interval_seconds == 0 {
         bail!("Collection interval cannot be 0");
     }
-    
+
     // Validate CPU thresholds
     if config.collectors.cpu.enabled {
         if config.collectors.cpu.load_warning_threshold <= 0.0 {
             bail!("CPU load warning threshold must be positive");
         }
-        
-        if config.collectors.cpu.load_critical_threshold <= config.collectors.cpu.load_warning_threshold {
+
+        if config.collectors.cpu.load_critical_threshold
+            <= config.collectors.cpu.load_warning_threshold
+        {
             bail!("CPU load critical threshold must be greater than warning threshold");
         }
-        
+
         if config.collectors.cpu.temperature_warning_threshold <= 0.0 {
             bail!("CPU temperature warning threshold must be positive");
         }
-        
-        if config.collectors.cpu.temperature_critical_threshold <= config.collectors.cpu.temperature_warning_threshold {
+
+        if config.collectors.cpu.temperature_critical_threshold
+            <= config.collectors.cpu.temperature_warning_threshold
+        {
             bail!("CPU temperature critical threshold must be greater than warning threshold");
         }
     }
-    
+
     // Validate memory thresholds
     if config.collectors.memory.enabled {
-        if config.collectors.memory.usage_warning_percent <= 0.0 || config.collectors.memory.usage_warning_percent > 100.0 {
+        if config.collectors.memory.usage_warning_percent <= 0.0
+            || config.collectors.memory.usage_warning_percent > 100.0
+        {
             bail!("Memory usage warning threshold must be between 0 and 100");
         }
-        
-        if config.collectors.memory.usage_critical_percent <= config.collectors.memory.usage_warning_percent 
-            || config.collectors.memory.usage_critical_percent > 100.0 {
+
+        if config.collectors.memory.usage_critical_percent
+            <= config.collectors.memory.usage_warning_percent
+            || config.collectors.memory.usage_critical_percent > 100.0
+        {
             bail!("Memory usage critical threshold must be between warning threshold and 100");
         }
     }
-    
+
     // Validate disk thresholds
     if config.collectors.disk.enabled {
-        if config.collectors.disk.usage_warning_percent <= 0.0 || config.collectors.disk.usage_warning_percent > 100.0 {
+        if config.collectors.disk.usage_warning_percent <= 0.0
+            || config.collectors.disk.usage_warning_percent > 100.0
+        {
             bail!("Disk usage warning threshold must be between 0 and 100");
         }
-        
-        if config.collectors.disk.usage_critical_percent <= config.collectors.disk.usage_warning_percent 
-            || config.collectors.disk.usage_critical_percent > 100.0 {
+
+        if config.collectors.disk.usage_critical_percent
+            <= config.collectors.disk.usage_warning_percent
+            || config.collectors.disk.usage_critical_percent > 100.0
+        {
             bail!("Disk usage critical threshold must be between warning threshold and 100");
         }
     }
-    
+
     // Validate SMTP configuration
     if config.notifications.enabled {
         if config.notifications.smtp_host.is_empty() {
             bail!("SMTP host cannot be empty when notifications are enabled");
         }
-        
+
         if config.notifications.smtp_port == 0 {
             bail!("SMTP port cannot be 0");
         }
-        
+
         if config.notifications.from_email.is_empty() {
             bail!("From email cannot be empty when notifications are enabled");
         }
-        
+
         if config.notifications.to_email.is_empty() {
             bail!("To email cannot be empty when notifications are enabled");
         }
-        
+
         // Basic email validation
         if !config.notifications.from_email.contains('@') {
             bail!("From email must contain @ symbol");
         }
-        
+
         if !config.notifications.to_email.contains('@') {
             bail!("To email must contain @ symbol");
         }
     }
-    
+
     // Validate cache configuration
     if config.cache.enabled {
         if config.cache.default_ttl_seconds == 0 {
             bail!("Cache TTL cannot be 0");
         }
-        
+
         if config.cache.max_entries == 0 {
             bail!("Cache max entries cannot be 0");
         }
     }
-    
+
     Ok(())
-}
+}