Reduce all command timeouts to 2-3 seconds max

With 10-second host heartbeat timeout, all command timeouts must be significantly lower to ensure total collection time stays under 10 seconds.

Changed timeouts:
- smartctl: 10s → 3s (critical: multiple drives queried sequentially)
- du: 5s → 2s
- lsblk: 5s → 2s
- systemctl list commands: 5s → 3s
- systemctl show/is-active: 3s → 2s
- docker commands: 5s → 3s
- df, ip commands: 3s → 2s

Total worst-case collection time now capped at more reasonable levels, preventing false host offline alerts from blocking operations.

agent/src/collectors/disk.rs

@@ -117,7 +117,7 @@ impl DiskCollector {
         let mut cmd = Command::new("lsblk");
         cmd.args(&["-rn", "-o", "NAME,MOUNTPOINT"]);
 
-        let output = run_command_with_timeout(cmd, 5).await
+        let output = run_command_with_timeout(cmd, 2).await
             .map_err(|e| CollectorError::SystemRead {
                 path: "block devices".to_string(),
                 error: e.to_string(),
@@ -427,7 +427,7 @@ impl DiskCollector {
             cmd.args(&["-a", &format!("/dev/{}", drive_name)]);
         }
 
-        let output = run_command_with_timeout(cmd, 10).await
+        let output = run_command_with_timeout(cmd, 3).await
             .map_err(|e| CollectorError::SystemRead {
                 path: format!("SMART data for {}", drive_name),
                 error: e.to_string(),
@@ -764,7 +764,7 @@ impl DiskCollector {
     fn get_drive_info_for_path(&self, path: &str) -> anyhow::Result<PoolDrive> {
         // Use lsblk to find the backing device with timeout
         let output = Command::new("timeout")
-            .args(&["5", "lsblk", "-rn", "-o", "NAME,MOUNTPOINT"])
+            .args(&["2", "lsblk", "-rn", "-o", "NAME,MOUNTPOINT"])
             .output()
             .map_err(|e| anyhow::anyhow!("Failed to run lsblk: {}", e))?;