Remove refresh functionality that causes dashboard to hang

- Remove 'r' key handler that was causing hang on refresh
- Remove RefreshRequested event and check_refresh_request method
- Remove send_refresh_commands function and ZMQ command protocol
- Remove refresh_requested field from App struct
- Clean up status line text (refresh -> tick)

The refresh functionality was causing the dashboard to become unresponsive
when pressing 'r' key. This removes all refresh-related code to fix the issue.

dashboard/src/app.rs

@@ -69,7 +69,6 @@ pub struct App {
     active_host_index: usize,
     show_help: bool,
     should_quit: bool,
-    refresh_requested: bool,
     last_tick: Instant,
     tick_count: u64,
     status: String,
@@ -107,7 +106,6 @@ impl App {
             active_host_index: 0,
             show_help: false,
             should_quit: false,
-            refresh_requested: false,
             last_tick: Instant::now(),
             tick_count: 0,
             status,
@@ -124,7 +122,7 @@ impl App {
         let host_count = self.hosts.len();
         let retention = self.history.retention();
         self.status = format!(
-            "Monitoring • hosts: {} • refresh: {:?} • retention: {:?}",
+            "Monitoring • hosts: {} • tick: {:?} • retention: {:?}",
             host_count, self.options.tick_rate, retention
         );
     }
@@ -139,10 +137,6 @@ impl App {
                 self.should_quit = true;
                 self.status = "Exiting…".to_string();
             }
-            KeyCode::Char('r') | KeyCode::Char('R') => {
-                self.refresh_requested = true;
-                self.status = "Refresh requested - sending commands to agents...".to_string();
-            }
             KeyCode::Left | KeyCode::Char('h') => {
                 self.select_previous_host();
             }
@@ -160,14 +154,6 @@ impl App {
         self.should_quit
     }
     
-    pub fn check_refresh_request(&mut self) -> bool {
-        if self.refresh_requested {
-            self.refresh_requested = false;
-            true
-        } else {
-            false
-        }
-    }
 
     #[allow(dead_code)]
     pub fn status_text(&self) -> &str {
@@ -353,10 +339,6 @@ impl App {
 
                 self.status = format!("Fetch failed • host: {} • {}", host, error);
             }
-            AppEvent::RefreshRequested => {
-                // Handle refresh command - will be implemented in the main loop
-                self.status = "Refresh command sent to all agents".to_string();
-            }
         }
     }
 
@@ -661,6 +643,5 @@ pub enum AppEvent {
         error: String,
         timestamp: DateTime<Utc>,
     },
-    RefreshRequested,
     Shutdown,
 }

dashboard/src/main.rs

@@ -53,7 +53,7 @@ struct Cli {
     #[arg(short = 'H', long, value_name = "HOST")]
     host: Option<String>,
 
-    /// Interval (ms) to refresh dashboard when idle
+    /// Interval (ms) for dashboard tick rate
     #[arg(long, default_value_t = 250)]
     tick_rate: u64,
 
@@ -154,10 +154,6 @@ fn run_app(
     while !app.should_quit() {
         drain_app_events(app, event_rx);
         
-        // Check for refresh requests
-        if app.check_refresh_request() {
-            send_refresh_commands(app)?;
-        }
         
         terminal.draw(|frame| ui::render(frame, app))?;
 
@@ -307,57 +303,6 @@ fn metrics_blocking_loop(
     Ok(())
 }
 
-fn send_refresh_commands(app: &mut App) -> Result<()> {
-    let endpoints = app.zmq_endpoints();
-    if endpoints.is_empty() {
-        return Ok(());
-    }
-    
-    let zmq_context = NativeZmqContext::new();
-    
-    for endpoint in endpoints {
-        // Convert metrics endpoint (6130) to command endpoint (6131)
-        let command_endpoint = endpoint.replace(":6130", ":6131");
-        
-        let socket = zmq_context.socket(zmq::REQ)?;
-        socket.set_linger(0)?;
-        socket.set_rcvtimeo(5000)?; // 5 second timeout
-        socket.set_sndtimeo(5000)?; // 5 second timeout
-        
-        match socket.connect(&command_endpoint) {
-            Ok(()) => {
-                debug!("Sending refresh command to {}", command_endpoint);
-                
-                match socket.send("refresh", 0) {
-                    Ok(()) => {
-                        // Wait for response
-                        match socket.recv_string(0) {
-                            Ok(Ok(response)) => {
-                                debug!("Refresh response from {}: {}", command_endpoint, response);
-                                // Update status via public method would be needed, for now just log
-                                debug!("Refresh sent to agents - response: {}", response);
-                            }
-                            Ok(Err(e)) => {
-                                warn!("String conversion error from {}: {:?}", command_endpoint, e);
-                            }
-                            Err(e) => {
-                                warn!("No response from {}: {}", command_endpoint, e);
-                            }
-                        }
-                    }
-                    Err(e) => {
-                        warn!("Failed to send refresh to {}: {}", command_endpoint, e);
-                    }
-                }
-            }
-            Err(e) => {
-                warn!("Failed to connect to command endpoint {}: {}", command_endpoint, e);
-            }
-        }
-    }
-    
-    Ok(())
-}
 
 fn handle_zmq_message(
     message: &NativeZmqMessage,