inspect_signal_decoders turned sigrok's explicit missing-decoder refusal
into execution_failure with rea doctor advice, while decode_signal_recording
already reported the same refusal as invalid_request on decoders.
The sigrok selector classifier now owns the unknown-ID match for both
selections: help names the decoder field and points to catalog discovery,
decoding keeps decoders/annotations. The provider passes each producer
command's caller selection to that one owner instead of per-call closures.
Installed decoders that fail to load and refusals naming other IDs remain
provider failures. The real-sigrok verifier now asserts the typed refusal
for both operations.
Fixes#5849
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>