feat(multi-rig): auto-discover per-rig audio ports via GetRigs

src/trx-client/trx-frontend/src/lib.rs

@@ -21,6 +21,7 @@ use trx_core::{DynResult, RigRequest, RigState};
 pub struct RemoteRigEntry {
     pub rig_id: String,
     pub state: RigSnapshot,
+    pub audio_port: Option<u16>,
 }
 
 /// Trait implemented by concrete frontends to expose a runner entrypoint.

src/trx-client/trx-frontend/trx-frontend-http-json/src/server.rs

@@ -244,6 +244,7 @@ fn snapshot_remote_rigs(context: &FrontendRuntimeContext) -> Vec<RigEntry> {
                 .map(|entry| RigEntry {
                     rig_id: entry.rig_id.clone(),
                     state: entry.state.clone(),
+                    audio_port: entry.audio_port,
                 })
                 .collect()
         })