[feat](trx-core): add capability flags and filter state for UI gating

Add five new boolean fields to RigCapabilities: tx, tx_limit,
vfo_switch, filter_controls, signal_meter. These drive which controls
the HTTP frontend shows or hides per rig type.

Add RigFilterState struct (bandwidth_hz, fir_taps, cw_center_hz) and
filter: Option<RigFilterState> to both RigState (skip-serialized) and
RigSnapshot (skip_serializing_if = None).

Add SetBandwidth and SetFirTaps to RigCommand; add default not-supported
implementations of set_bandwidth, set_fir_taps, and filter_state to
the RigCat trait.

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

src/trx-core/src/lib.rs

@@ -14,4 +14,4 @@ pub use rig::AudioSource;
 pub use rig::command::RigCommand;
 pub use rig::request::RigRequest;
 pub use rig::response::{RigError, RigResult};
-pub use rig::state::{RigMode, RigSnapshot, RigState};
+pub use rig::state::{RigFilterState, RigMode, RigSnapshot, RigState};

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

@@ -30,4 +30,6 @@ pub enum RigCommand {
     ResetCwDecoder,
     ResetFt8Decoder,
     ResetWsprDecoder,
+    SetBandwidth(u32),
+    SetFirTaps(u32),
 }

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

@@ -512,7 +512,9 @@ pub fn command_from_rig_command(cmd: RigCommand) -> Box<dyn RigCommandHandler> {
         | RigCommand::ResetAprsDecoder
         | RigCommand::ResetCwDecoder
         | RigCommand::ResetFt8Decoder
-        | RigCommand::ResetWsprDecoder => Box::new(GetSnapshotCommand),
+        | RigCommand::ResetWsprDecoder
+        | RigCommand::SetBandwidth(_)
+        | RigCommand::SetFirTaps(_) => Box::new(GetSnapshotCommand),
     }
 }
 
@@ -553,6 +555,11 @@ mod tests {
                         rit: false,
                         rpt: false,
                         split: false,
+                        tx: true,
+                        tx_limit: true,
+                        vfo_switch: true,
+                        filter_controls: false,
+                        signal_meter: true,
                     },
                     access: RigAccessMethod::Serial {
                         path: "/dev/test".to_string(),
@@ -607,6 +614,11 @@ mod tests {
                         rit: false,
                         rpt: false,
                         split: false,
+                        tx: true,
+                        tx_limit: true,
+                        vfo_switch: true,
+                        filter_controls: false,
+                        signal_meter: true,
                     },
                     access: RigAccessMethod::Serial {
                         path: "/dev/test".to_string(),

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

@@ -450,6 +450,11 @@ mod tests {
                 rit: false,
                 rpt: false,
                 split: false,
+                tx: true,
+                tx_limit: true,
+                vfo_switch: true,
+                filter_controls: false,
+                signal_meter: true,
             },
             access: RigAccessMethod::Serial {
                 path: "/dev/test".to_string(),

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

@@ -51,6 +51,16 @@ pub struct RigCapabilities {
     pub rit: bool,
     pub rpt: bool,
     pub split: bool,
+    /// Backend supports transmit: PTT, power on/off, TX meters, TX audio.
+    pub tx: bool,
+    /// Backend supports get_tx_limit / set_tx_limit.
+    pub tx_limit: bool,
+    /// Backend supports toggle_vfo.
+    pub vfo_switch: bool,
+    /// Backend supports runtime filter adjustment (bandwidth, FIR taps).
+    pub filter_controls: bool,
+    /// Backend returns a meaningful RX signal strength value.
+    pub signal_meter: bool,
 }
 
 fn default_min_freq_step_hz() -> u64 {
@@ -112,6 +122,27 @@ pub trait RigCat: Rig + Send {
     fn unlock<'a>(&'a mut self) -> Pin<Box<dyn Future<Output = DynResult<()>> + Send + 'a>>;
 
     fn as_audio_source(&self) -> Option<&dyn AudioSource> { None }
+
+    fn set_bandwidth<'a>(
+        &'a mut self,
+        _bandwidth_hz: u32,
+    ) -> Pin<Box<dyn Future<Output = DynResult<()>> + Send + 'a>> {
+        Box::pin(std::future::ready(Err(Box::new(
+            response::RigError::not_supported("set_bandwidth"),
+        ) as Box<dyn std::error::Error + Send + Sync>)))
+    }
+
+    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>)))
+    }
+
+    /// Return the current filter state if this backend supports filter controls.
+    fn filter_state(&self) -> Option<state::RigFilterState> { None }
 }
 
 /// Snapshot of a rig's status that every backend can expose.

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

@@ -42,6 +42,10 @@ pub struct RigState {
     pub cw_wpm: u32,
     #[serde(default)]
     pub cw_tone_hz: u32,
+    /// Filter state for backends that support runtime filter adjustment.
+    /// Skipped in serde; flows into RigSnapshot via snapshot().
+    #[serde(skip)]
+    pub filter: Option<RigFilterState>,
     #[serde(default, skip_serializing)]
     pub aprs_decode_reset_seq: u64,
     #[serde(default, skip_serializing)]
@@ -127,6 +131,7 @@ impl RigState {
             cw_auto: true,
             cw_wpm: 15,
             cw_tone_hz: 700,
+            filter: None,
             aprs_decode_reset_seq: 0,
             cw_decode_reset_seq: 0,
             ft8_decode_reset_seq: 0,
@@ -186,6 +191,7 @@ impl RigState {
             cw_tone_hz: snapshot.cw_tone_hz,
             ft8_decode_enabled: snapshot.ft8_decode_enabled,
             wspr_decode_enabled: snapshot.wspr_decode_enabled,
+            filter: snapshot.filter,
             aprs_decode_reset_seq: 0,
             cw_decode_reset_seq: 0,
             ft8_decode_reset_seq: 0,
@@ -223,6 +229,7 @@ impl RigState {
             cw_tone_hz: self.cw_tone_hz,
             ft8_decode_enabled: self.ft8_decode_enabled,
             wspr_decode_enabled: self.wspr_decode_enabled,
+            filter: self.filter.clone(),
         })
     }
 
@@ -249,6 +256,14 @@ impl RigState {
     }
 }
 
+/// Current filter/DSP state for backends that support runtime filter adjustment.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct RigFilterState {
+    pub bandwidth_hz: u32,
+    pub fir_taps: u32,
+    pub cw_center_hz: u32,
+}
+
 /// Read-only projection of state shared with clients.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct RigSnapshot {
@@ -283,4 +298,6 @@ pub struct RigSnapshot {
     pub cw_wpm: u32,
     #[serde(default)]
     pub cw_tone_hz: u32,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub filter: Option<RigFilterState>,
 }