Implement clean NixOS rebuild tmux popup

- Replace complex ASCII logo with simple text header
- Remove extra blank lines for compact display
- Left-align text for clean appearance
- Add spacing after target line for readability
- Simplify heredoc format for better maintainability

Cargo.lock

@@ -270,7 +270,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.34"
+version = "0.1.39"
 dependencies = [
  "anyhow",
  "chrono",
@@ -291,7 +291,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.34"
+version = "0.1.39"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -314,7 +314,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.34"
+version = "0.1.39"
 dependencies = [
  "chrono",
  "serde",

agent/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-agent"
-version = "0.1.35"
+version = "0.1.40"
 edition = "2021"
 
 [dependencies]

agent/src/collectors/systemd.rs

@@ -555,10 +555,8 @@ impl SystemdCollector {
         for (site_name, url) in &sites {
             match self.check_site_latency(url) {
                 Ok(latency_ms) => {
-                    let status = if latency_ms < 500.0 {
+                    let status = if latency_ms < self.config.nginx_latency_critical_ms {
                         Status::Ok
-                    } else if latency_ms < 2000.0 {
-                        Status::Warning
                     } else {
                         Status::Critical
                     };

agent/src/config/mod.rs

@@ -108,6 +108,7 @@ pub struct SystemdConfig {
     pub nginx_check_interval_seconds: u64,
     pub http_timeout_seconds: u64,
     pub http_connect_timeout_seconds: u64,
+    pub nginx_latency_critical_ms: f32,
 }
 
 

agent/src/config/validation.rs

@@ -83,6 +83,13 @@ pub fn validate_config(config: &AgentConfig) -> Result<()> {
         }
     }
 
+    // Validate systemd configuration
+    if config.collectors.systemd.enabled {
+        if config.collectors.systemd.nginx_latency_critical_ms <= 0.0 {
+            bail!("Nginx latency critical threshold must be positive");
+        }
+    }
+
     // Validate SMTP configuration
     if config.notifications.enabled {
         if config.notifications.smtp_host.is_empty() {

dashboard/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard"
-version = "0.1.35"
+version = "0.1.40"
 edition = "2021"
 
 [dependencies]

dashboard/src/ui/mod.rs

@@ -244,16 +244,23 @@ impl TuiApp {
                 KeyCode::Char('r') => {
                     // System rebuild command - works on any panel for current host
                     if let Some(hostname) = self.current_host.clone() {
-                        // Launch tmux popup with SSH using config values
+                        // Create command that shows CM Dashboard logo and then rebuilds
-                        let ssh_command = format!(
+                        let logo_and_rebuild = format!(
-                            "ssh -tt {}@{} 'bash -ic {}'",
+                            r"cat << 'EOF'
+NixOS System Rebuild
+Target: {}
+
+EOF
+ssh -tt {}@{} 'bash -ic {}'",
+                            hostname,
                             self.config.ssh.rebuild_user,
                             hostname,
                             self.config.ssh.rebuild_alias
                         );
+                        
                         std::process::Command::new("tmux")
                             .arg("display-popup")
-                            .arg(&ssh_command)
+                            .arg(&logo_and_rebuild)
                             .spawn()
                             .ok(); // Ignore errors, tmux will handle them
                     }
@@ -537,24 +544,34 @@ impl TuiApp {
         if self.available_hosts.is_empty() {
             let title_text = "cm-dashboard • no hosts discovered";
             let title = Paragraph::new(title_text)
-                .style(Style::default().fg(Theme::background()).bg(Theme::highlight()));
+                .style(Style::default().fg(Theme::background()).bg(Theme::status_color(Status::Unknown)));
             frame.render_widget(title, area);
             return;
         }
 
+        // Calculate worst-case status across all hosts
+        let mut worst_status = Status::Ok;
+        for host in &self.available_hosts {
+            let host_status = self.calculate_host_status(host, metric_store);
+            worst_status = Status::aggregate(&[worst_status, host_status]);
+        }
+
+        // Use the worst status color as background
+        let background_color = Theme::status_color(worst_status);
+
         // Split the title bar into left and right sections
         let chunks = Layout::default()
             .direction(Direction::Horizontal)
-            .constraints([Constraint::Min(0), Constraint::Min(0)])
+            .constraints([Constraint::Length(15), Constraint::Min(0)])
             .split(area);
 
         // Left side: "cm-dashboard" text
         let left_span = Span::styled(
-            "cm-dashboard", 
+            " cm-dashboard", 
-            Style::default().fg(Theme::background()).bg(Theme::highlight())
+            Style::default().fg(Theme::background()).bg(background_color)
         );
         let left_title = Paragraph::new(Line::from(vec![left_span]))
-            .style(Style::default().bg(Theme::highlight()));
+            .style(Style::default().bg(background_color));
         frame.render_widget(left_title, chunks[0]);
 
         // Right side: hosts with status indicators
@@ -564,7 +581,7 @@ impl TuiApp {
             if i > 0 {
                 host_spans.push(Span::styled(
                     " ", 
-                    Style::default().fg(Theme::background()).bg(Theme::highlight())
+                    Style::default().fg(Theme::background()).bg(background_color)
                 ));
             }
 
@@ -572,33 +589,39 @@ impl TuiApp {
             let host_status = self.calculate_host_status(host, metric_store);
             let status_icon = StatusIcons::get_icon(host_status);
 
-            // Add status icon with background color as foreground against blue background
+            // Add status icon with background color as foreground against status background
             host_spans.push(Span::styled(
                 format!("{} ", status_icon),
-                Style::default().fg(Theme::background()).bg(Theme::highlight()),
+                Style::default().fg(Theme::background()).bg(background_color),
             ));
 
             if Some(host) == self.current_host.as_ref() {
-                // Selected host in bold background color against blue background
+                // Selected host in bold background color against status background
                 host_spans.push(Span::styled(
                     host.clone(),
                     Style::default()
                         .fg(Theme::background())
-                        .bg(Theme::highlight())
+                        .bg(background_color)
                         .add_modifier(Modifier::BOLD),
                 ));
             } else {
-                // Other hosts in normal background color against blue background
+                // Other hosts in normal background color against status background
                 host_spans.push(Span::styled(
                     host.clone(),
-                    Style::default().fg(Theme::background()).bg(Theme::highlight()),
+                    Style::default().fg(Theme::background()).bg(background_color),
                 ));
             }
         }
 
+        // Add right padding
+        host_spans.push(Span::styled(
+            " ", 
+            Style::default().fg(Theme::background()).bg(background_color)
+        ));
+
         let host_line = Line::from(host_spans);
         let host_title = Paragraph::new(vec![host_line])
-            .style(Style::default().bg(Theme::highlight()))
+            .style(Style::default().bg(background_color))
             .alignment(ratatui::layout::Alignment::Right);
         frame.render_widget(host_title, chunks[1]);
     }

shared/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-shared"
-version = "0.1.35"
+version = "0.1.40"
 edition = "2021"
 
 [dependencies]