fix(lint): resolve E005, E105, E320, E330, E340, E405, E616
- E005: extract helpers to shorten long functions (discover_cmd, main_cmd, fuzz suites)
- E105: replace catch-all exception handlers with Eio.Exn.Io
- E320: shorten long identifiers in fuzz_cfdp and fuzz_meross
- E330: rename main_cmd to cmd
- E340: use err_cidr helper instead of Error (Fmt.str ...)
- E405: add missing docs for unbind_matter, is_meross_device, pp_info
- E616: use failf instead of fail (Fmt.str ...) in meross tests