fix: trim command whitespace in Docker script to avoid trailing newline issues

YAML literal blocks (|) include trailing newlines, causing commands like
'grep --version\n' to be passed to the shell. When quoted with %q, this
becomes 'grep --version\n' which the shell interprets as '--versionn'.

Now trimming whitespace from commands before embedding in the script.

Author: inercia

pkg/runner/docker.go

@@ -423,12 +423,13 @@ func (r *Docker) createScriptFile(shell string, cmd string, env []string) (strin
 		r.logger.Debug("Added preparation command to script: %s", r.opts.PrepareCommand)
 	}
 
-	// Add the main command
+	// Add the main command (trim whitespace to avoid issues with trailing newlines from YAML literal blocks)
 	content.WriteString("# Main command to execute\n")
+	trimmedCmd := strings.TrimSpace(cmd)
 	if shell != "" {
-		fmt.Fprintf(&content, "exec %s -c %q\n", shell, cmd)
+		fmt.Fprintf(&content, "exec %s -c %q\n", shell, trimmedCmd)
 	} else {
-		fmt.Fprintf(&content, "exec sh -c %q\n", cmd)
+		fmt.Fprintf(&content, "exec sh -c %q\n", trimmedCmd)
 	}
 
 	// Write the content to the file