Add SAS Service for Ctrl+Alt+Del support

- New guruconnect-sas-service binary (runs as SYSTEM)
- Named pipe IPC for agent-to-service communication
- Multi-tier SAS approach: service > sas.dll > fallback
- Service auto-install/uninstall helpers in startup.rs

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

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

agent/src/input/keyboard.rs

@@ -129,15 +129,21 @@ impl KeyboardController {
 
     /// Send Secure Attention Sequence (Ctrl+Alt+Delete)
     ///
-    /// Note: This requires special privileges on Windows.
-    /// The agent typically needs to run as SYSTEM or use SAS API.
+    /// This uses a multi-tier approach:
+    /// 1. Try the GuruConnect SAS Service (runs as SYSTEM, handles via named pipe)
+    /// 2. Try the sas.dll directly (requires SYSTEM privileges)
+    /// 3. Fallback to key simulation (won't work on secure desktop)
     #[cfg(windows)]
     pub fn send_sas(&mut self) -> Result<()> {
-        // Try using the SAS library if available
-        // For now, we'll attempt to send the key combination
-        // This won't work in all contexts due to Windows security
+        // Tier 1: Try the SAS service (named pipe IPC to SYSTEM service)
+        if let Ok(()) = crate::sas_client::request_sas() {
+            tracing::info!("SAS sent via GuruConnect SAS Service");
+            return Ok(());
+        }
 
-        // Load the sas.dll and call SendSAS if available
+        tracing::info!("SAS service not available, trying direct sas.dll...");
+
+        // Tier 2: Try using the sas.dll directly (requires SYSTEM privileges)
         use windows::Win32::System::LibraryLoader::{GetProcAddress, LoadLibraryW};
         use windows::core::PCWSTR;
 
@@ -151,13 +157,14 @@ impl KeyboardController {
                     // SendSAS takes a BOOL parameter: FALSE for Ctrl+Alt+Del
                     let send_sas: extern "system" fn(i32) = std::mem::transmute(proc);
                     send_sas(0); // FALSE = Ctrl+Alt+Del
+                    tracing::info!("SAS sent via direct sas.dll call");
                     return Ok(());
                 }
             }
         }
 
-        // Fallback: Try sending the keys (won't work without proper privileges)
-        tracing::warn!("SAS library not available, Ctrl+Alt+Del may not work");
+        // Tier 3: Fallback - try sending the keys (won't work on secure desktop)
+        tracing::warn!("SAS service and sas.dll not available, Ctrl+Alt+Del may not work");
 
         // VK codes
         const VK_CONTROL: u16 = 0x11;