[feat](trx-rs): expose WFM stereo denoise toggle in UI

Wire the StereoDenoise processor through the full stack:
- Add SetWfmDenoise command variant and RigCat trait method (trx-core)
- Add wfm_denoise field to RigFilterState with default true
- Add protocol command and bidirectional mapping (trx-protocol)
- Add rig_task command handler (trx-server)
- Implement set_wfm_denoise in SoapySdrRig backend
- Add /set_wfm_denoise API endpoint (trx-frontend-http)
- Add denoise checkbox in WFM controls with SSE sync and
  localStorage persistence

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

src/trx-protocol/src/codec.rs

@@ -301,6 +301,7 @@ mod tests {
                 wfm_deemphasis_us: 75,
                 wfm_stereo: true,
                 wfm_stereo_detected: false,
+                wfm_denoise: true,
             }),
             ..minimal_snapshot()
         })
@@ -340,6 +341,7 @@ mod tests {
                 wfm_deemphasis_us: 50,
                 wfm_stereo: true,
                 wfm_stereo_detected: true,
+                wfm_denoise: true,
             }),
             ..minimal_snapshot()
         };

src/trx-protocol/src/mapping.rs

@@ -53,6 +53,7 @@ pub fn client_command_to_rig(cmd: ClientCommand) -> RigCommand {
             RigCommand::SetWfmDeemphasis(deemphasis_us)
         }
         ClientCommand::SetWfmStereo { enabled } => RigCommand::SetWfmStereo(enabled),
+        ClientCommand::SetWfmDenoise { enabled } => RigCommand::SetWfmDenoise(enabled),
         ClientCommand::GetSpectrum => RigCommand::GetSpectrum,
     }
 }
@@ -99,6 +100,7 @@ pub fn rig_command_to_client(cmd: RigCommand) -> ClientCommand {
             ClientCommand::SetWfmDeemphasis { deemphasis_us }
         }
         RigCommand::SetWfmStereo(enabled) => ClientCommand::SetWfmStereo { enabled },
+        RigCommand::SetWfmDenoise(enabled) => ClientCommand::SetWfmDenoise { enabled },
         RigCommand::GetSpectrum => ClientCommand::GetSpectrum,
     }
 }

src/trx-protocol/src/types.rs

@@ -41,6 +41,7 @@ pub enum ClientCommand {
     SetSdrGain { gain_db: f64 },
     SetWfmDeemphasis { deemphasis_us: u32 },
     SetWfmStereo { enabled: bool },
+    SetWfmDenoise { enabled: bool },
     GetSpectrum,
 }