Add comprehensive timeouts to all blocking system commands

Fixes random host disconnections caused by blocking operations preventing timely ZMQ packet transmission.

Changes:
- Add run_command_with_timeout() wrapper using tokio for async command execution
- Apply 10s timeout to smartctl (prevents 30+ second hangs on failing drives)
- Apply 5s timeout to du, lsblk, systemctl list commands
- Apply 3s timeout to systemctl show/is-active, df, ip commands
- Apply 2s timeout to hostname command
- Use system 'timeout' command for sync operations where async not needed

Critical fixes:
- smartctl: Failing drives could block for 30+ seconds per drive
- du: Large directories (Docker, PostgreSQL) could block 10-30+ seconds
- systemctl/docker: Commands could block indefinitely during system issues

With 1-second collection interval and 10-second heartbeat timeout, any blocking operation >10s causes false "host offline" alerts. These timeouts ensure collection completes quickly even during system degradation.

agent/src/collectors/mod.rs

@@ -1,6 +1,8 @@
 use async_trait::async_trait;
 use cm_dashboard_shared::{AgentData};
-
+use std::process::{Command, Output};
+use std::time::Duration;
+use tokio::time::timeout;
 
 pub mod backup;
 pub mod cpu;
@@ -13,6 +15,20 @@ pub mod systemd;
 
 pub use error::CollectorError;
 
+/// Run a command with a timeout to prevent blocking
+pub async fn run_command_with_timeout(mut cmd: Command, timeout_secs: u64) -> std::io::Result<Output> {
+    let timeout_duration = Duration::from_secs(timeout_secs);
+
+    match timeout(timeout_duration, tokio::task::spawn_blocking(move || cmd.output())).await {
+        Ok(Ok(result)) => result,
+        Ok(Err(e)) => Err(std::io::Error::new(std::io::ErrorKind::Other, e)),
+        Err(_) => Err(std::io::Error::new(
+            std::io::ErrorKind::TimedOut,
+            format!("Command timed out after {} seconds", timeout_secs)
+        )),
+    }
+}
+
 
 /// Base trait for all collectors with direct structured data output
 #[async_trait]