[refactor](trx-frontend-http): simplify auto-squelch to single-click action

Revert toggle approach back to a simple button: click sets squelch to
noise floor + 6 dB when spectrum data is available, or Off otherwise.

https://claude.ai/code/session_01TDQyrZiPKfWGATVWPsLmHT
Signed-off-by: Claude <noreply@anthropic.com>

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

@@ -7670,44 +7670,28 @@ if (sdrSquelchEl) {
 }
 
 const sdrSquelchAutoBtn = document.getElementById("sdr-squelch-auto");
-let sdrSquelchAutoActive = false;
-function updateSdrSquelchAutoBtn() {
-  if (!sdrSquelchAutoBtn) return;
-  sdrSquelchAutoBtn.textContent = sdrSquelchAutoActive ? "Auto" : "Off";
-  sdrSquelchAutoBtn.classList.toggle("active", sdrSquelchAutoActive);
-}
-function applySdrSquelchPct(pct) {
-  if (sdrSquelchEl) {
-    sdrSquelchEl.value = String(pct);
-    updateSdrSquelchPctLabel();
-    saveSetting("sdrSquelchPct", pct);
-  }
-  submitSdrSquelchPercent(pct);
-}
 if (sdrSquelchAutoBtn) {
-  updateSdrSquelchAutoBtn();
   sdrSquelchAutoBtn.addEventListener("click", () => {
     if (!sdrSquelchSupported) return;
-    if (sdrSquelchAutoActive) {
+    let pct = 0; // default: Off
-      // Toggle off: set squelch to 0% (Open)
-      sdrSquelchAutoActive = false;
-      updateSdrSquelchAutoBtn();
-      applySdrSquelchPct(0);
-      return;
-    }
-    // Toggle on: set squelch to noise floor + 6 dB
     const data = lastSpectrumData || window.lastSpectrumData;
-    if (!data || !Array.isArray(data.bins) || data.bins.length === 0) return;
+    if (data && Array.isArray(data.bins) && data.bins.length > 0) {
-    const noiseDb = estimateNoiseFloorDb(data.bins);
+      const noiseDb = estimateNoiseFloorDb(data.bins);
-    if (noiseDb == null || !Number.isFinite(noiseDb)) return;
+      if (noiseDb != null && Number.isFinite(noiseDb)) {
-    const thresholdDb = noiseDb + 6;
+        // Set threshold slightly above noise floor so squelch closes on noise
-    const clamped = Math.max(SDR_SQUELCH_MIN_DB, Math.min(SDR_SQUELCH_MAX_DB, thresholdDb));
+        const thresholdDb = noiseDb + 6;
-    const pct = clampSdrSquelchPercent(
+        const clamped = Math.max(SDR_SQUELCH_MIN_DB, Math.min(SDR_SQUELCH_MAX_DB, thresholdDb));
-      ((clamped - SDR_SQUELCH_MIN_DB) / (SDR_SQUELCH_MAX_DB - SDR_SQUELCH_MIN_DB)) * 100,
+        pct = clampSdrSquelchPercent(
-    );
+          ((clamped - SDR_SQUELCH_MIN_DB) / (SDR_SQUELCH_MAX_DB - SDR_SQUELCH_MIN_DB)) * 100,
-    sdrSquelchAutoActive = true;
+        );
-    updateSdrSquelchAutoBtn();
+      }
-    applySdrSquelchPct(pct);
+    }
+    if (sdrSquelchEl) {
+      sdrSquelchEl.value = String(pct);
+      updateSdrSquelchPctLabel();
+      saveSetting("sdrSquelchPct", pct);
+    }
+    submitSdrSquelchPercent(pct);
   });
 }
 

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

@@ -374,7 +374,7 @@
                 <button id="tx-audio-btn" type="button">Transmit Audio</button>
                 <label class="vol-label">RX<input type="range" id="rx-vol" min="0" max="100" value="80" class="vol-slider" /><small class="vol-pct" id="rx-vol-pct">80%</small></label>
                 <label class="vol-label">TX<input type="range" id="tx-vol" min="0" max="100" value="80" class="vol-slider" /><small class="vol-pct" id="tx-vol-pct">80%</small></label>
-                <label class="vol-label" id="sdr-squelch-wrap" style="display:none;">SQL<input type="range" id="sdr-squelch" min="0" max="100" value="0" class="vol-slider" /><small class="vol-pct" id="sdr-squelch-pct">Open</small><button id="sdr-squelch-auto" type="button" class="sql-auto-btn" title="Set squelch to current noise level">Off</button></label>
+                <label class="vol-label" id="sdr-squelch-wrap" style="display:none;">SQL<input type="range" id="sdr-squelch" min="0" max="100" value="0" class="vol-slider" /><small class="vol-pct" id="sdr-squelch-pct">Open</small><button id="sdr-squelch-auto" type="button" class="sql-auto-btn" title="Set squelch to current noise level">Auto</button></label>
                 <div id="audio-level">
                   <div id="audio-level-fill"></div>
                 </div>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/style.css

@@ -1286,10 +1286,6 @@ small { color: var(--text-muted); }
   border-radius: 3px;
   cursor: pointer;
 }
-.sql-auto-btn.active {
-  background: var(--accent-green);
-  color: #000;
-}
 .vol-slider {
   -webkit-appearance: none;
   appearance: none;