refactor(peadm_spec): improve error handling in add_inventory_hostnames plan

- Replace parallelize with map for better readability
- Add error handling for hostname command execution
- Add error handling for inventory file update command

Author: CoMfUcIoS

spec/acceptance/peadm_spec/plans/add_inventory_hostnames.pp

@@ -4,10 +4,15 @@
   $t = get_targets('*')
   wait_until_available($t)
 
-  parallelize($t) |$target| {
-    $fqdn = run_command('hostname -f', $target)
-    $target.set_var('certname', $fqdn.first['stdout'].chomp)
-    $command = "yq eval '(.groups[].targets[] | select(.uri == \"${target.uri}\").name) = \"${target.vars['certname']}\"' -i ${inventory_file}"
-    run_command($command, 'localhost')
+  $t.map |$target| {
+    $fqdn = run_command('hostname -f', $target).first
+    if $fqdn['exit_code'] != 0 {
+      fail("Failed to get FQDN for target ${target.name}: ${fqdn['stderr']}")
+    }
+    $command = "yq eval '(.groups[].targets[] | select(.uri == \"${target.uri}\").name) = \"${fqdn['stdout'].chomp}\"' -i ${inventory_file}"
+    $result = run_command($command, 'localhost').first
+    if $result['exit_code'] != 0 {
+      fail("Failed to update inventory file for target ${uri}: ${result['stderr']}")
+    }
   }
 }