[fix](trx-frontend-http): make setRigFrequency fire-and-forget

The HTTP round-trip for set_freq blocks on the server processing the
command (mpsc → TCP → rig hardware → response). With optimistic local
updates, CSS overlay, and SSE snap-back guard already in place, there is
no reason to await the network call. All callers (jog, freq input, spectrum
click, RDS AF tune) now return immediately after the optimistic update.

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

src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js

@@ -1943,32 +1943,32 @@ async function ensureTunedBandwidthCoverage(freqHz, bandwidthHz = coverageGuardB
 let _freqOptimisticHz = null;
 let _freqOptimisticSeq = 0;
 
-async function setRigFrequency(freqHz) {
+function setRigFrequency(freqHz) {
   const targetHz = Math.round(freqHz);
   if (!freqAllowed(targetHz)) {
     showUnsupportedFreqPopup(targetHz);
     throw new Error(`Unsupported frequency: ${targetHz}`);
   }
-  // Optimistic local update before any network round-trip.
+  // Optimistic local update — visual is instant via CSS overlay + guard.
   const prevFreqHz = lastFreqHz;
   const seq = ++_freqOptimisticSeq;
   _freqOptimisticHz = targetHz;
   applyLocalTunedFrequency(targetHz);
-  try {
-    // set_freq and set_center_freq are independent server operations — run in parallel.
-    await Promise.all([
+  // Fire-and-forget: network calls run in background. The SSE stream will
+  // push the confirmed frequency; the optimistic guard prevents snap-back.
+  Promise.all([
     postPath(`/set_freq?hz=${targetHz}`),
     ensureTunedBandwidthCoverage(targetHz),
-    ]);
-  } catch (err) {
-    // Roll back the optimistic update so the spectrum view stays on the
-    // actual server-side frequency (e.g. when the user loses control access).
-    if (prevFreqHz != null) applyLocalTunedFrequency(prevFreqHz, true);
-    throw err;
-  } finally {
-    // Only clear the guard if no newer optimistic call has superseded us.
-    if (_freqOptimisticSeq === seq) _freqOptimisticHz = null;
+  ]).catch((err) => {
+    // Roll back only if no newer optimistic call has superseded this one.
+    if (_freqOptimisticSeq === seq && prevFreqHz != null) {
+      _freqOptimisticHz = null;
+      applyLocalTunedFrequency(prevFreqHz, true);
     }
+    console.warn("setRigFrequency failed:", err);
+  }).finally(() => {
+    if (_freqOptimisticSeq === seq) _freqOptimisticHz = null;
+  });
 }
 
 function spectrumBinIndexForHz(data, hz) {
@@ -3509,7 +3509,7 @@ pttBtn.addEventListener("click", async () => {
   }
 });
 
-async function applyFreqFromInput() {
+function applyFreqFromInput() {
   const parsedRaw = parseFreqInput(freqEl.value, jogUnit);
   const parsed = alignFreqToRigStep(parsedRaw);
   if (parsed === null) {
@@ -3521,17 +3521,8 @@ async function applyFreqFromInput() {
     return;
   }
   freqDirty = false;
-  freqEl.disabled = true;
-  showHint("Setting frequency…");
-  try {
-    await setRigFrequency(parsed);
-    showHint("Freq set", 1500);
-  } catch (err) {
-    showHint("Set freq failed", 2000);
-    console.error(err);
-  } finally {
-    freqEl.disabled = false;
-  }
+  // setRigFrequency is fire-and-forget; visual update is instant.
+  setRigFrequency(parsed);
 }
 
 async function applyCenterFreqFromInput() {
@@ -3616,7 +3607,7 @@ function setJogDivisor(divisor) {
   applyJogStep();
 }
 
-async function jogFreq(direction) {
+function jogFreq(direction) {
   if (lastLocked) { showHint("Locked", 1500); return; }
   if (lastFreqHz === null) return;
   const newHz = alignFreqToRigStep(lastFreqHz + direction * jogStep);
@@ -3626,22 +3617,8 @@ async function jogFreq(direction) {
   }
   jogAngle = (jogAngle + direction * 15) % 360;
   jogIndicator.style.transform = `translateX(-50%) rotate(${jogAngle}deg)`;
-  showHint("Setting frequency…");
-  // Optimistic local state update — visible to the user before the network call.
-  // Set the guard BEFORE yielding so SSE cannot snap back during the yield.
-  ++_freqOptimisticSeq;
-  _freqOptimisticHz = newHz;
-  applyLocalTunedFrequency(newHz);
-  // Yield so the browser paints the updated freq display before the network
-  // round-trip begins. Chrome's INP tracking ends at the yield point.
-  await yieldToMain();
-  try {
-    await setRigFrequency(newHz);
-    showHint("Freq set", 1000);
-  } catch (err) {
-    showHint("Set freq failed", 2000);
-    console.error(err);
-  }
+  // setRigFrequency is fire-and-forget; visual update is instant.
+  setRigFrequency(newHz);
 }
 
 jogDownBtn.addEventListener("click", () => jogFreq(-1));
@@ -8837,15 +8814,11 @@ function formatRdsAfMHz(hz) {
   return `${(hz / 1_000_000).toFixed(1)} MHz`;
 }
 
-async function tuneRdsAlternativeFrequency(hz) {
+function tuneRdsAlternativeFrequency(hz) {
   if (!Number.isFinite(hz) || hz <= 0) return;
   const targetHz = Math.round(hz);
-  try {
-    await setRigFrequency(targetHz);
+  setRigFrequency(targetHz);
   showHint(`Tuned ${formatRdsAfMHz(targetHz)}`, 1200);
-  } catch (_) {
-    showHint("Set freq failed", 1500);
-  }
 }
 
 function renderRdsAlternativeFrequencies(list) {
@@ -9688,7 +9661,7 @@ function handleSpectrumClick(e, canvasEl) {
   const cssX = e.clientX - rect.left;
   const targetHz = spectrumTargetHzAt(cssX, rect.width, lastSpectrumData);
   if (!Number.isFinite(targetHz)) return;
-  setRigFrequency(targetHz).catch(() => {});
+  setRigFrequency(targetHz);
 }
 
 if (spectrumCanvas) {