ListPrintersTool
Lists installed print service plugins (resolved from the android.printservice.PrintService intent) and the host app's own active print jobs from PrintManager.getPrintJobs. Note: this does NOT enumerate individual physical printers — discovery happens inside the system print UI.
No permissions required. Returns an error if PrintManager is unavailable. Read-only.
Output keys: print_services (each with package, name), service_count, active_jobs (each with id, label, state), active_job_count.