[refactor](trx-core): remove SetFirTaps command and fir_taps from state

Drop the SetFirTaps RigCommand variant, remove the set_fir_taps default
trait method from Rig, and remove the fir_taps field from RigFilterState.
Tap count is now derived automatically from audio bandwidth in the DSP
layer rather than being a user-facing control.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stanislaw Grams <stanislawgrams@gmail.com>

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

@@ -39,7 +39,6 @@ pub enum RigCommand {
     ResetFt2Decoder,
     ResetWsprDecoder,
     SetBandwidth(u32),
-    SetFirTaps(u32),
     SetSdrGain(f64),
     SetSdrLnaGain(f64),
     SetSdrAgc(bool),

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

@@ -521,7 +521,6 @@ pub fn command_from_rig_command(cmd: RigCommand) -> Box<dyn RigCommandHandler> {
         | RigCommand::ResetFt2Decoder
         | RigCommand::ResetWsprDecoder
         | RigCommand::SetBandwidth(_)
-        | RigCommand::SetFirTaps(_)
         | RigCommand::SetSdrGain(_)
         | RigCommand::SetSdrLnaGain(_)
         | RigCommand::SetSdrAgc(_)

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

@@ -57,7 +57,7 @@ pub struct RigCapabilities {
     pub tx_limit: bool,
     /// Backend supports toggle_vfo.
     pub vfo_switch: bool,
-    /// Backend supports runtime filter adjustment (bandwidth, FIR taps).
+    /// Backend supports runtime filter adjustment (bandwidth).
     pub filter_controls: bool,
     /// Backend returns a meaningful RX signal strength value.
     pub signal_meter: bool,
@@ -160,16 +160,6 @@ pub trait RigCat: Rig + Send {
         )))
     }
 
-    fn set_fir_taps<'a>(
-        &'a mut self,
-        _taps: u32,
-    ) -> Pin<Box<dyn Future<Output = DynResult<()>> + Send + 'a>> {
-        Box::pin(std::future::ready(Err(
-            Box::new(response::RigError::not_supported("set_fir_taps"))
-                as Box<dyn std::error::Error + Send + Sync>,
-        )))
-    }
-
     fn set_wfm_deemphasis<'a>(
         &'a mut self,
         _deemphasis_us: u32,

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

@@ -308,7 +308,6 @@ impl RigState {
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct RigFilterState {
     pub bandwidth_hz: u32,
-    pub fir_taps: u32,
     pub cw_center_hz: u32,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub sdr_gain_db: Option<f64>,