Add system tray icon with menu for agent

- Added tray-icon and muda crates for tray functionality
- Tray icon shows green circle when connected
- Menu displays: session code, machine name, End Session option
- End Session menu item cleanly terminates the agent
- Tray events processed in session main loop

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

agent/src/main.rs

@@ -14,13 +14,14 @@ mod encoder;
 mod input;
 mod session;
 mod transport;
+mod tray;
 
 pub mod proto {
     include!(concat!(env!("OUT_DIR"), "/guruconnect.rs"));
 }
 
 use anyhow::Result;
-use tracing::{info, error, Level};
+use tracing::{info, error, warn, Level};
 use tracing_subscriber::FmtSubscriber;
 
 #[cfg(windows)]
@@ -122,19 +123,51 @@ async fn run_agent(config: config::Config) -> Result<()> {
     // Create session manager
     let mut session = session::SessionManager::new(config.clone());
     let is_support_session = config.support_code.is_some();
+    let hostname = config.hostname();
+
+    // Create tray icon
+    let tray = match tray::TrayController::new(&hostname, config.support_code.as_deref()) {
+        Ok(t) => {
+            info!("Tray icon created");
+            Some(t)
+        }
+        Err(e) => {
+            warn!("Failed to create tray icon: {}. Continuing without tray.", e);
+            None
+        }
+    };
 
     // Connect to server and run main loop
     loop {
         info!("Connecting to server...");
 
+        // Check if user requested exit via tray before connecting
+        if let Some(ref t) = tray {
+            if t.exit_requested() {
+                info!("Exit requested by user");
+                return Ok(());
+            }
+        }
+
         match session.connect().await {
             Ok(_) => {
                 info!("Connected to server");
 
-                // Run session until disconnect
-                if let Err(e) = session.run().await {
+                // Update tray status
+                if let Some(ref t) = tray {
+                    t.update_status("Status: Connected");
+                }
+
+                // Run session until disconnect, passing tray for event processing
+                if let Err(e) = session.run_with_tray(tray.as_ref()).await {
                     let error_msg = e.to_string();
 
+                    // Check if this is a user-initiated exit
+                    if error_msg.contains("USER_EXIT") {
+                        info!("Session ended by user");
+                        return Ok(());
+                    }
+
                     // Check if this is a cancellation
                     if error_msg.contains("SESSION_CANCELLED") {
                         info!("Session was cancelled by technician");
@@ -173,6 +206,14 @@ async fn run_agent(config: config::Config) -> Result<()> {
             return Ok(());
         }
 
+        // Check if user requested exit via tray
+        if let Some(ref t) = tray {
+            if t.exit_requested() {
+                info!("Exit requested by user");
+                return Ok(());
+            }
+        }
+
         // Wait before reconnecting (only for persistent agent connections)
         info!("Reconnecting in 5 seconds...");
         tokio::time::sleep(tokio::time::Duration::from_secs(5)).await;