[feat](trx-rs): add configurable noise blanker for SoapySDR backend

IQ-domain impulse noise blanker using exponential-smoothing RMS tracker. Samples exceeding threshold × running RMS are replaced with the last clean sample. Configurable via [sdr.noise_blanker] in TOML config and runtime via POST /set_sdr_noise_blanker API.

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

src/trx-protocol/src/codec.rs

@@ -316,6 +316,8 @@ mod tests {
                 sdr_agc_enabled: None,
                 sdr_squelch_enabled: None,
                 sdr_squelch_threshold_db: None,
+                sdr_nb_enabled: None,
+                sdr_nb_threshold: None,
                 wfm_deemphasis_us: 75,
                 wfm_stereo: true,
                 wfm_stereo_detected: false,
@@ -358,6 +360,8 @@ mod tests {
                 sdr_agc_enabled: None,
                 sdr_squelch_enabled: None,
                 sdr_squelch_threshold_db: None,
+                sdr_nb_enabled: None,
+                sdr_nb_threshold: None,
                 wfm_deemphasis_us: 50,
                 wfm_stereo: true,
                 wfm_stereo_detected: true,

src/trx-protocol/src/mapping.rs

@@ -65,6 +65,9 @@ pub fn client_command_to_rig(cmd: ClientCommand) -> RigCommand {
             enabled,
             threshold_db,
         },
+        ClientCommand::SetSdrNoiseBlanker { enabled, threshold } => {
+            RigCommand::SetSdrNoiseBlanker { enabled, threshold }
+        }
         ClientCommand::SetWfmDeemphasis { deemphasis_us } => {
             RigCommand::SetWfmDeemphasis(deemphasis_us)
         }
@@ -128,6 +131,9 @@ pub fn rig_command_to_client(cmd: RigCommand) -> ClientCommand {
             enabled,
             threshold_db,
         },
+        RigCommand::SetSdrNoiseBlanker { enabled, threshold } => {
+            ClientCommand::SetSdrNoiseBlanker { enabled, threshold }
+        }
         RigCommand::SetWfmDeemphasis(deemphasis_us) => {
             ClientCommand::SetWfmDeemphasis { deemphasis_us }
         }

src/trx-protocol/src/types.rs

@@ -48,6 +48,7 @@ pub enum ClientCommand {
     SetSdrLnaGain { gain_db: f64 },
     SetSdrAgc { enabled: bool },
     SetSdrSquelch { enabled: bool, threshold_db: f64 },
+    SetSdrNoiseBlanker { enabled: bool, threshold: f64 },
     SetWfmDeemphasis { deemphasis_us: u32 },
     SetWfmStereo { enabled: bool },
     SetWfmDenoise { level: WfmDenoiseLevel },