[feat](trx-frontend-http): add noise blanker controls to SDR settings UI

Add checkbox to enable/disable NB and number input for threshold (1-100).
Controls are hidden by default and shown when the server reports NB support
via SSE filter state updates.

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

@@ -2944,6 +2944,19 @@ function render(update) {
       );
     }
     updateSdrSquelchControlVisibility();
+    const hasSdrNbEnabled = typeof update.filter.sdr_nb_enabled === "boolean";
+    const hasSdrNbThreshold = typeof update.filter.sdr_nb_threshold === "number";
+    if (hasSdrNbEnabled || hasSdrNbThreshold) {
+      sdrNbSupported = true;
+      if (sdrNbWrapEl) sdrNbWrapEl.style.display = "";
+      if (sdrNbThresholdControlsEl) sdrNbThresholdControlsEl.style.display = "";
+      if (hasSdrNbEnabled && sdrNbEnabledEl) {
+        sdrNbEnabledEl.checked = update.filter.sdr_nb_enabled;
+      }
+      if (hasSdrNbThreshold && sdrNbThresholdEl && document.activeElement !== sdrNbThresholdEl) {
+        sdrNbThresholdEl.value = String(Math.round(update.filter.sdr_nb_threshold));
+      }
+    }
   }
   if (typeof update.show_sdr_gain_control === "boolean") {
     if (sdrSettingsRowEl) sdrSettingsRowEl.style.display = update.show_sdr_gain_control ? "" : "none";
@@ -7281,6 +7294,12 @@ const sdrSquelchPctEl = document.getElementById("sdr-squelch-pct");
 const SDR_SQUELCH_MIN_DB = -120;
 const SDR_SQUELCH_MAX_DB = -30;
 let syncFromServerSdrSquelch = false;
+const sdrNbWrapEl = document.getElementById("sdr-nb-wrap");
+const sdrNbEnabledEl = document.getElementById("sdr-nb-enabled");
+const sdrNbThresholdControlsEl = document.getElementById("sdr-nb-threshold-controls");
+const sdrNbThresholdEl = document.getElementById("sdr-nb-threshold");
+const sdrNbThresholdSetBtn = document.getElementById("sdr-nb-threshold-set");
+let sdrNbSupported = false;
 
 // Hide audio row if audio is not configured on the server
 fetch("/audio", { method: "GET" }).then((r) => {
@@ -7490,6 +7509,37 @@ if (sdrLnaGainEl) {
     }
   });
 }
+function submitSdrNbState() {
+  if (!sdrNbSupported) return;
+  const enabled = sdrNbEnabledEl ? sdrNbEnabledEl.checked : false;
+  const threshold = sdrNbThresholdEl ? Number.parseFloat(sdrNbThresholdEl.value) : 10;
+  if (!Number.isFinite(threshold) || threshold < 1 || threshold > 100) return;
+  postPath(
+    `/set_sdr_noise_blanker?enabled=${enabled ? "true" : "false"}&threshold=${encodeURIComponent(threshold)}`,
+  ).catch(() => {});
+}
+if (sdrNbEnabledEl) {
+  sdrNbEnabledEl.addEventListener("change", () => {
+    submitSdrNbState();
+  });
+}
+function submitSdrNbThreshold() {
+  if (!sdrNbThresholdEl) return;
+  const parsed = Number.parseFloat(sdrNbThresholdEl.value);
+  if (!Number.isFinite(parsed) || parsed < 1 || parsed > 100) return;
+  submitSdrNbState();
+}
+if (sdrNbThresholdSetBtn) {
+  sdrNbThresholdSetBtn.addEventListener("click", submitSdrNbThreshold);
+}
+if (sdrNbThresholdEl) {
+  sdrNbThresholdEl.addEventListener("keydown", (ev) => {
+    if (ev.key === "Enter") {
+      ev.preventDefault();
+      submitSdrNbThreshold();
+    }
+  });
+}
 function updateWfmControls() {
   if (!wfmControlsCol) return;
   const mode = (modeEl && modeEl.value ? modeEl.value : "").toUpperCase();

src/trx-client/trx-frontend/trx-frontend-http/assets/web/index.html

@@ -284,6 +284,19 @@
                   </label>
                   <button id="sdr-lna-gain-set" type="button" class="wfm-inline-btn">Set</button>
                 </div>
+                <label class="wfm-control" id="sdr-nb-wrap" style="display:none;">
+                  <span class="wfm-control-label">Noise Blanker</span>
+                  <div style="height:2.1rem; display:flex; align-items:center;">
+                    <input type="checkbox" id="sdr-nb-enabled">
+                  </div>
+                </label>
+                <div class="wfm-gain-group" id="sdr-nb-threshold-controls" style="display:none;">
+                  <label class="wfm-control">
+                    <span class="wfm-control-label">NB Threshold</span>
+                    <input id="sdr-nb-threshold" class="status-input" type="number" min="1" max="100" step="1" inputmode="decimal">
+                  </label>
+                  <button id="sdr-nb-threshold-set" type="button" class="wfm-inline-btn">Set</button>
+                </div>
               </div>
             </div>
             <div class="full-row label-below-row" id="vchan-row">