Implement real-time terminal popup for system rebuild operations

- Add terminal popup UI component with 80% screen coverage and terminal styling
- Extend ZMQ protocol with CommandOutputMessage for streaming output
- Implement real-time output streaming in agent system rebuild handler
- Add keyboard controls (ESC/Q to close, ↑↓ to scroll) for popup interaction
- Fix system panel Build display to show actual NixOS build instead of config hash
- Update service filters in README with wildcard patterns for better matching
- Add periodic progress updates during nixos-rebuild execution
- Integrate command output handling in dashboard main loop

dashboard/src/app.rs

@@ -268,6 +268,26 @@ impl Dashboard {
                         tui_app.update_metrics(&self.metric_store);
                     }
                 }
+                
+                // Also check for command output messages
+                if let Ok(Some(cmd_output)) = self.zmq_consumer.receive_command_output().await {
+                    debug!(
+                        "Received command output from {}: {}",
+                        cmd_output.hostname,
+                        cmd_output.output_line
+                    );
+
+                    // Forward to TUI if not headless
+                    if let Some(ref mut tui_app) = self.tui_app {
+                        tui_app.add_terminal_output(&cmd_output.hostname, cmd_output.output_line);
+                        
+                        // Close popup when command completes
+                        if cmd_output.is_complete {
+                            tui_app.close_terminal_popup(&cmd_output.hostname);
+                        }
+                    }
+                }
+                
                 last_metrics_check = Instant::now();
             }
 

dashboard/src/communication/mod.rs

@@ -1,5 +1,5 @@
 use anyhow::Result;
-use cm_dashboard_shared::{MessageEnvelope, MessageType, MetricMessage};
+use cm_dashboard_shared::{CommandOutputMessage, MessageEnvelope, MessageType, MetricMessage};
 use tracing::{debug, error, info, warn};
 use zmq::{Context, Socket, SocketType};
 
@@ -103,6 +103,43 @@ impl ZmqConsumer {
         Ok(())
     }
 
+    /// Receive command output from any connected agent (non-blocking)  
+    pub async fn receive_command_output(&mut self) -> Result<Option<CommandOutputMessage>> {
+        match self.subscriber.recv_bytes(zmq::DONTWAIT) {
+            Ok(data) => {
+                // Deserialize envelope
+                let envelope: MessageEnvelope = serde_json::from_slice(&data)
+                    .map_err(|e| anyhow::anyhow!("Failed to deserialize envelope: {}", e))?;
+
+                // Check message type
+                match envelope.message_type {
+                    MessageType::CommandOutput => {
+                        let cmd_output = envelope
+                            .decode_command_output()
+                            .map_err(|e| anyhow::anyhow!("Failed to decode command output: {}", e))?;
+
+                        debug!(
+                            "Received command output from {}: {}",
+                            cmd_output.hostname,
+                            cmd_output.output_line
+                        );
+
+                        Ok(Some(cmd_output))
+                    }
+                    _ => Ok(None), // Not a command output message
+                }
+            }
+            Err(zmq::Error::EAGAIN) => {
+                // No message available (non-blocking mode)
+                Ok(None)
+            }
+            Err(e) => {
+                error!("ZMQ receive error: {}", e);
+                Err(anyhow::anyhow!("ZMQ receive error: {}", e))
+            }
+        }
+    }
+
     /// Receive metrics from any connected agent (non-blocking)
     pub async fn receive_metrics(&mut self) -> Result<Option<MetricMessage>> {
         match self.subscriber.recv_bytes(zmq::DONTWAIT) {
@@ -132,6 +169,10 @@ impl ZmqConsumer {
                         debug!("Received heartbeat");
                         Ok(None) // Don't return heartbeats as metrics
                     }
+                    MessageType::CommandOutput => {
+                        debug!("Received command output (will be handled by receive_command_output)");
+                        Ok(None) // Command output handled by separate method
+                    }
                     _ => {
                         debug!("Received non-metrics message: {:?}", envelope.message_type);
                         Ok(None)

dashboard/src/ui/mod.rs

@@ -92,6 +92,51 @@ impl HostWidgets {
     }
 }
 
+/// Terminal popup for streaming command output
+#[derive(Clone)]
+pub struct TerminalPopup {
+    /// Is the popup currently visible
+    pub visible: bool,
+    /// Command being executed
+    pub command_type: CommandType,
+    /// Target hostname
+    pub hostname: String,
+    /// Target service/operation name
+    pub target: String,
+    /// Output lines collected so far
+    pub output_lines: Vec<String>,
+    /// Scroll offset for the output
+    pub scroll_offset: usize,
+    /// Start time of the operation
+    pub start_time: Instant,
+}
+
+impl TerminalPopup {
+    pub fn new(command_type: CommandType, hostname: String, target: String) -> Self {
+        Self {
+            visible: true,
+            command_type,
+            hostname,
+            target,
+            output_lines: Vec::new(),
+            scroll_offset: 0,
+            start_time: Instant::now(),
+        }
+    }
+
+    pub fn add_output_line(&mut self, line: String) {
+        self.output_lines.push(line);
+        // Auto-scroll to bottom when new content arrives
+        if self.output_lines.len() > 20 {
+            self.scroll_offset = self.output_lines.len().saturating_sub(20);
+        }
+    }
+
+    pub fn close(&mut self) {
+        self.visible = false;
+    }
+}
+
 /// Main TUI application
 pub struct TuiApp {
     /// Widget states per host (hostname -> HostWidgets)
@@ -108,6 +153,8 @@ pub struct TuiApp {
     should_quit: bool,
     /// Track if user manually navigated away from localhost
     user_navigated_away: bool,
+    /// Terminal popup for streaming command output
+    terminal_popup: Option<TerminalPopup>,
 }
 
 impl TuiApp {
@@ -120,6 +167,7 @@ impl TuiApp {
             focused_panel: PanelType::System, // Start with System panel focused
             should_quit: false,
             user_navigated_away: false,
+            terminal_popup: None,
         }
     }
 
@@ -250,6 +298,38 @@ impl TuiApp {
     /// Handle keyboard input
     pub fn handle_input(&mut self, event: Event) -> Result<Option<UiCommand>> {
         if let Event::Key(key) = event {
+            // If terminal popup is visible, handle popup-specific keys first
+            if let Some(ref mut popup) = self.terminal_popup {
+                if popup.visible {
+                    match key.code {
+                        KeyCode::Esc => {
+                            popup.close();
+                            self.terminal_popup = None;
+                            return Ok(None);
+                        }
+                        KeyCode::Up => {
+                            popup.scroll_offset = popup.scroll_offset.saturating_sub(1);
+                            return Ok(None);
+                        }
+                        KeyCode::Down => {
+                            let max_scroll = if popup.output_lines.len() > 20 {
+                                popup.output_lines.len() - 20
+                            } else {
+                                0
+                            };
+                            popup.scroll_offset = (popup.scroll_offset + 1).min(max_scroll);
+                            return Ok(None);
+                        }
+                        KeyCode::Char('q') => {
+                            popup.close();
+                            self.terminal_popup = None;
+                            return Ok(None);
+                        }
+                        _ => return Ok(None), // Consume all other keys when popup is open
+                    }
+                }
+            }
+
             match key.code {
                 KeyCode::Char('q') => {
                     self.should_quit = true;
@@ -266,6 +346,12 @@ impl TuiApp {
                             // System rebuild command
                             if let Some(hostname) = self.current_host.clone() {
                                 self.start_command(&hostname, CommandType::SystemRebuild, hostname.clone());
+                                // Open terminal popup for real-time output
+                                self.terminal_popup = Some(TerminalPopup::new(
+                                    CommandType::SystemRebuild,
+                                    hostname.clone(),
+                                    "NixOS Rebuild".to_string()
+                                ));
                                 return Ok(Some(UiCommand::SystemRebuild { hostname }));
                             }
                         }
@@ -473,6 +559,25 @@ impl TuiApp {
         }
     }
 
+    /// Add output line to terminal popup
+    pub fn add_terminal_output(&mut self, hostname: &str, line: String) {
+        if let Some(ref mut popup) = self.terminal_popup {
+            if popup.hostname == hostname && popup.visible {
+                popup.add_output_line(line);
+            }
+        }
+    }
+
+    /// Close terminal popup for a specific hostname
+    pub fn close_terminal_popup(&mut self, hostname: &str) {
+        if let Some(ref mut popup) = self.terminal_popup {
+            if popup.hostname == hostname {
+                popup.close();
+                self.terminal_popup = None;
+            }
+        }
+    }
+
     /// Check for rebuild completion by detecting agent hash changes
     pub fn check_rebuild_completion(&mut self, metric_store: &MetricStore) {
         let mut hosts_to_complete = Vec::new();
@@ -636,6 +741,13 @@ impl TuiApp {
 
         // Render statusbar at the bottom
         self.render_statusbar(frame, main_chunks[2]); // main_chunks[2] is the statusbar area
+
+        // Render terminal popup on top of everything else
+        if let Some(ref popup) = self.terminal_popup {
+            if popup.visible {
+                self.render_terminal_popup(frame, size, popup);
+            }
+        }
     }
 
     /// Render btop-style minimal title with host status colors
@@ -835,4 +947,112 @@ impl TuiApp {
         }
     }
 
+    /// Render terminal popup with streaming output
+    fn render_terminal_popup(&self, frame: &mut Frame, area: Rect, popup: &TerminalPopup) {
+        use ratatui::{
+            style::{Color, Modifier, Style},
+            text::{Line, Span},
+            widgets::{Block, Borders, Clear, Paragraph, Wrap},
+        };
+
+        // Calculate popup size (80% of screen, centered)
+        let popup_width = area.width * 80 / 100;
+        let popup_height = area.height * 80 / 100;
+        let popup_x = (area.width - popup_width) / 2;
+        let popup_y = (area.height - popup_height) / 2;
+        
+        let popup_area = Rect {
+            x: popup_x,
+            y: popup_y,
+            width: popup_width,
+            height: popup_height,
+        };
+
+        // Clear background
+        frame.render_widget(Clear, popup_area);
+
+        // Create terminal-style block
+        let title = format!(" {} → {} ({:.1}s) ", 
+            popup.hostname, 
+            popup.target,
+            popup.start_time.elapsed().as_secs_f32()
+        );
+        
+        let block = Block::default()
+            .title(title)
+            .borders(Borders::ALL)
+            .border_style(Style::default().fg(Color::Cyan))
+            .style(Style::default().bg(Color::Black));
+
+        let inner_area = block.inner(popup_area);
+        frame.render_widget(block, popup_area);
+
+        // Render output content
+        let available_height = inner_area.height as usize;
+        let total_lines = popup.output_lines.len();
+        
+        // Calculate which lines to show based on scroll offset
+        let start_line = popup.scroll_offset;
+        let end_line = (start_line + available_height).min(total_lines);
+        
+        let visible_lines: Vec<Line> = popup.output_lines[start_line..end_line]
+            .iter()
+            .map(|line| {
+                // Style output lines with terminal colors
+                if line.contains("error") || line.contains("Error") || line.contains("failed") {
+                    Line::from(Span::styled(line.clone(), Style::default().fg(Color::Red)))
+                } else if line.contains("warning") || line.contains("Warning") {
+                    Line::from(Span::styled(line.clone(), Style::default().fg(Color::Yellow)))
+                } else if line.contains("building") || line.contains("Building") {
+                    Line::from(Span::styled(line.clone(), Style::default().fg(Color::Blue)))
+                } else if line.contains("✓") || line.contains("success") || line.contains("completed") {
+                    Line::from(Span::styled(line.clone(), Style::default().fg(Color::Green)))
+                } else {
+                    Line::from(Span::styled(line.clone(), Style::default().fg(Color::White)))
+                }
+            })
+            .collect();
+
+        let content = Paragraph::new(visible_lines)
+            .wrap(Wrap { trim: false })
+            .style(Style::default().bg(Color::Black));
+
+        frame.render_widget(content, inner_area);
+
+        // Render scroll indicator if needed
+        if total_lines > available_height {
+            let scroll_info = format!(" {}% ", 
+                if total_lines > 0 { 
+                    (end_line * 100) / total_lines 
+                } else { 
+                    100 
+                }
+            );
+            
+            let scroll_area = Rect {
+                x: popup_area.x + popup_area.width - scroll_info.len() as u16 - 1,
+                y: popup_area.y + popup_area.height - 1,
+                width: scroll_info.len() as u16,
+                height: 1,
+            };
+            
+            let scroll_widget = Paragraph::new(scroll_info)
+                .style(Style::default().fg(Color::Cyan).bg(Color::Black));
+            frame.render_widget(scroll_widget, scroll_area);
+        }
+
+        // Instructions at bottom
+        let instructions = " ESC/Q: Close • ↑↓: Scroll ";
+        let instructions_area = Rect {
+            x: popup_area.x + 1,
+            y: popup_area.y + popup_area.height - 1,
+            width: instructions.len() as u16,
+            height: 1,
+        };
+        
+        let instructions_widget = Paragraph::new(instructions)
+            .style(Style::default().fg(Color::Gray).bg(Color::Black));
+        frame.render_widget(instructions_widget, instructions_area);
+    }
+
 }

dashboard/src/ui/widgets/system.rs

@@ -422,9 +422,19 @@ impl SystemWidget {
             Span::styled("NixOS:", Typography::widget_title())
         ]));
         
+        let build_text = self.nixos_build.as_deref().unwrap_or("unknown");
+        lines.push(Line::from(vec![
+            Span::styled(format!("Build: {}", build_text), Typography::secondary())
+        ]));
+        
         let config_text = self.config_hash.as_deref().unwrap_or("unknown");
         lines.push(Line::from(vec![
-            Span::styled(format!("Build: {}", config_text), Typography::secondary())
+            Span::styled(format!("Config: {}", config_text), Typography::secondary())
+        ]));
+        
+        let users_text = self.active_users.as_deref().unwrap_or("unknown");
+        lines.push(Line::from(vec![
+            Span::styled(format!("Active users: {}", users_text), Typography::secondary())
         ]));
         
         let agent_hash_text = self.agent_hash.as_deref().unwrap_or("unknown");