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/main.rs

@@ -16,6 +16,7 @@ mod chat;
 mod config;
 mod encoder;
 mod input;
+mod sas_client;
 mod session;
 mod startup;
 mod transport;