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 = "0.1.37"
+version = "0.1.39"
 dependencies = [
  "anyhow",
  "chrono",
@@ -291,7 +291,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.37"
+version = "0.1.39"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -314,7 +314,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.37"
+version = "0.1.39"
 dependencies = [
  "chrono",
  "serde",

agent/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-agent"
-version = "0.1.38"
+version = "0.1.40"
 edition = "2021"
 
 [dependencies]

dashboard/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard"
-version = "0.1.38"
+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
-                        let ssh_command = format!(
-                            "ssh -tt {}@{} 'bash -ic {}'",
+                        // Create command that shows CM Dashboard logo and then rebuilds
+                        let logo_and_rebuild = format!(
+                            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
                     }

shared/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-shared"
-version = "0.1.38"
+version = "0.1.40"
 edition = "2021"
 
 [dependencies]