[fix](trx-backend-soapysdr,trx-frontend-http): make wfm mono mode real

Co-authored-by: Codex <codex@openai.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-core/src/rig/command.rs

@@ -34,6 +34,7 @@ pub enum RigCommand {
     SetBandwidth(u32),
     SetFirTaps(u32),
     SetWfmDeemphasis(u32),
+    SetWfmStereo(bool),
     SetWfmDenoise(bool),
     GetSpectrum,
 }

src/trx-core/src/rig/controller/handlers.rs

@@ -517,6 +517,7 @@ pub fn command_from_rig_command(cmd: RigCommand) -> Box<dyn RigCommandHandler> {
         | RigCommand::SetBandwidth(_)
         | RigCommand::SetFirTaps(_)
         | RigCommand::SetWfmDeemphasis(_)
+        | RigCommand::SetWfmStereo(_)
         | RigCommand::SetWfmDenoise(_)
         | RigCommand::GetSpectrum => Box::new(GetSnapshotCommand),
     }

src/trx-core/src/rig/mod.rs

@@ -175,6 +175,16 @@ pub trait RigCat: Rig + Send {
         )))
     }
 
+    fn set_wfm_stereo<'a>(
+        &'a mut self,
+        _enabled: bool,
+    ) -> Pin<Box<dyn Future<Output = DynResult<()>> + Send + 'a>> {
+        Box::pin(std::future::ready(Err(
+            Box::new(response::RigError::not_supported("set_wfm_stereo"))
+                as Box<dyn std::error::Error + Send + Sync>,
+        )))
+    }
+
     /// Return the current filter state if this backend supports filter controls.
     fn filter_state(&self) -> Option<state::RigFilterState> {
         None

src/trx-core/src/rig/state.rs

@@ -271,6 +271,8 @@ pub struct RigFilterState {
     pub cw_center_hz: u32,
     #[serde(default = "default_wfm_deemphasis_us")]
     pub wfm_deemphasis_us: u32,
+    #[serde(default = "default_wfm_stereo")]
+    pub wfm_stereo: bool,
     #[serde(default = "default_wfm_denoise")]
     pub wfm_denoise: bool,
 }
@@ -283,6 +285,10 @@ fn default_wfm_denoise() -> bool {
     true
 }
 
+fn default_wfm_stereo() -> bool {
+    true
+}
+
 /// Spectrum data from SDR backends (FFT magnitude over the full capture bandwidth).
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct SpectrumData {