Add detected IP display in dashboard Agent row

Display the connection IP address that the dashboard is configured to use
for each host below the Agent version information. Shows which network
path (local/Tailscale) is being used for connections based on host
configuration.

Features:
- Display detected IP below Agent row in system widget
- Uses existing host configuration connection logic
- Shows actual IP being used for dashboard connections

dashboard/src/ui/widgets/system.rs

@@ -439,7 +439,7 @@ impl Widget for SystemWidget {
 
 impl SystemWidget {
     /// Render with scroll offset support
-    pub fn render_with_scroll(&mut self, frame: &mut Frame, area: Rect, scroll_offset: usize, hostname: &str) {
+    pub fn render_with_scroll(&mut self, frame: &mut Frame, area: Rect, scroll_offset: usize, hostname: &str, config: Option<&crate::config::DashboardConfig>) {
         let mut lines = Vec::new();
 
         // NixOS section
@@ -457,6 +457,16 @@ impl SystemWidget {
             Span::styled(format!("Agent: {}", agent_version_text), Typography::secondary())
         ]));
         
+        // Display detected connection IP
+        if let Some(config) = config {
+            if let Some(host_details) = config.hosts.get(hostname) {
+                let detected_ip = host_details.get_connection_ip(hostname);
+                lines.push(Line::from(vec![
+                    Span::styled(format!("IP: {}", detected_ip), Typography::secondary())
+                ]));
+            }
+        }
+        
 
         // CPU section
         lines.push(Line::from(vec![