[fix](trx-ft8): drop FT8 messages that fail to unpack

Skip decoded candidates where ftx_message_decode() returns a non-OK
status instead of forwarding a synthetic error string.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/decoders/trx-ft8/src/ft8_wrapper.c

@@ -225,9 +225,7 @@ int ft8_decoder_decode(ft8_decoder_t* dec, ft8_decode_result_t* out, int max_res
         ftx_message_offsets_t offsets;
         ftx_message_rc_t unpack_status = ftx_message_decode(&message, &hash_if, text, &offsets);
         if (unpack_status != FTX_MESSAGE_RC_OK)
-        {
-            snprintf(text, sizeof(text), "Error [%d] while unpacking!", (int)unpack_status);
-        }
+            continue;
 
         ft8_decode_result_t* dst = &out[num_decoded];
         strncpy(dst->text, text, sizeof(dst->text) - 1);