fix: always use sudo for agent install (remove fallback check)

The sudo -n check was incorrectly detecting that sudo required a
password, causing fallback to plain bash without root permissions.
Now we always run the installer via sudo bash, consistent with how
all other SSH commands work (systemctl, reboot, etc.).

src/Services/AgentService.php

@@ -51,11 +51,9 @@ class AgentService
 
         $b64 = base64_encode($script);
         $remoteCommand = sprintf(
-            'echo %s | base64 -d | (sudo -n true 2>/dev/null && sudo bash -s -- %s %s || bash -s -- %s %s) 2>&1',
+            'echo %s | base64 -d | sudo bash -s -- %s %s 2>&1',
             escapeshellarg($b64),
             escapeshellarg($serverUrl),
-            escapeshellarg($agentKey),
-            escapeshellarg($serverUrl),
             escapeshellarg($agentKey)
         );