Add agent version reporting and display

- Agent reports version via agent_version metric using nix store hash
- Dashboard displays agent version in system widget
- Foundation for cross-host version comparison
- Both agent -V and dashboard show versions

agent/src/agent.rs

@@ -9,7 +9,7 @@ use crate::config::AgentConfig;
 use crate::metrics::MetricCollectionManager;
 use crate::notifications::NotificationManager;
 use crate::status::HostStatusManager;
-use cm_dashboard_shared::{Metric, MetricMessage};
+use cm_dashboard_shared::{Metric, MetricMessage, MetricValue, Status};
 
 pub struct Agent {
     hostname: String,
@@ -162,6 +162,10 @@ impl Agent {
         let host_status_metric = self.host_status_manager.get_host_status_metric();
         metrics.push(host_status_metric);
 
+        // Add agent version metric for cross-host version comparison
+        let version_metric = self.get_agent_version_metric();
+        metrics.push(version_metric);
+
         if metrics.is_empty() {
             debug!("No metrics to broadcast");
             return Ok(());
@@ -183,6 +187,39 @@ impl Agent {
         }
     }
 
+    /// Create agent version metric for cross-host version comparison
+    fn get_agent_version_metric(&self) -> Metric {
+        // Get version from executable path (same logic as main.rs get_version)
+        let version = self.get_agent_version();
+        
+        Metric::new(
+            "agent_version".to_string(),
+            MetricValue::String(version),
+            Status::Ok,
+        )
+    }
+
+    /// Get agent version from executable path
+    fn get_agent_version(&self) -> String {
+        match std::env::current_exe() {
+            Ok(exe_path) => {
+                let exe_str = exe_path.to_string_lossy();
+                
+                // Extract Nix store hash from path
+                if let Some(hash_part) = exe_str.strip_prefix("/nix/store/") {
+                    if let Some(hash) = hash_part.split('-').next() {
+                        if hash.len() >= 8 {
+                            return hash[..8].to_string();
+                        }
+                    }
+                }
+                
+                "unknown".to_string()
+            },
+            Err(_) => "unknown".to_string()
+        }
+    }
+
     async fn handle_commands(&mut self) -> Result<()> {
         // Try to receive commands (non-blocking)
         match self.zmq_handler.try_receive_command() {

agent/src/main.rs

@@ -13,10 +13,26 @@ mod status;
 
 use agent::Agent;
 
+/// Get version showing cm-dashboard-agent package hash for easy deployment verification
+fn get_version() -> &'static str {
+    // Get the path of the current executable
+    let exe_path = std::env::current_exe().expect("Failed to get executable path");
+    let exe_str = exe_path.to_string_lossy();
+    
+    // Extract Nix store hash from path like /nix/store/HASH-cm-dashboard-v0.1.8/bin/cm-dashboard-agent
+    let hash_part = exe_str.strip_prefix("/nix/store/").expect("Not a nix store path");
+    let hash = hash_part.split('-').next().expect("Invalid nix store path format");
+    assert!(hash.len() >= 8, "Hash too short");
+    
+    // Return first 8 characters of nix store hash
+    let short_hash = hash[..8].to_string();
+    Box::leak(short_hash.into_boxed_str())
+}
+
 #[derive(Parser)]
 #[command(name = "cm-dashboard-agent")]
 #[command(about = "CM Dashboard metrics agent with individual metric collection")]
-#[command(version)]
+#[command(version = get_version())]
 struct Cli {
     /// Increase logging verbosity (-v, -vv)
     #[arg(short, long, action = clap::ArgAction::Count)]

dashboard/src/ui/widgets/system.rs

@@ -339,9 +339,9 @@ impl Widget for SystemWidget {
                         self.active_users = Some(users.clone());
                     }
                 }
-                "system_agent_hash" => {
-                    if let MetricValue::String(hash) = &metric.value {
-                        self.agent_hash = Some(hash.clone());
+                "agent_version" => {
+                    if let MetricValue::String(version) = &metric.value {
+                        self.agent_hash = Some(version.clone());
                     }
                 }