[feat](trx-frontend-http): make the SQL label the squelch switch

Clicking SQL turns the squelch on and off.  The label and the button
beside it said the same thing twice — one naming the control, the other
reading "On" or "Off" — where the name itself is the obvious target, and
the dot already carries the state: grey when off, green while the gate
passes, amber while it holds.

The pressed state is on the label, so the switch reads the same to a
screen reader as it looks.

Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/trx-frontend-http/frontend/src/app.ts

@@ -5343,15 +5343,15 @@ function renderSdrSquelch() {
   }
   if (sdrSquelchDbEl) sdrSquelchDbEl.disabled = !sdrSquelchSupported;
   if (sdrSquelchToggleBtn) {
-    sdrSquelchToggleBtn.textContent = sdrSquelchEnabled ? "On" : "Off";
     sdrSquelchToggleBtn.setAttribute("aria-pressed", String(sdrSquelchEnabled));
+    sdrSquelchToggleBtn.title = sdrSquelchEnabled ? "Turn the squelch off" : "Turn the squelch on";
   }
   const state = !sdrSquelchEnabled ? "off" : (sdrSquelchIsPassing() ? "open" : "closed");
   if (sdrSquelchStateEl) {
     sdrSquelchStateEl.dataset.state = state;
-    sdrSquelchStateEl.setAttribute(
+    sdrSquelchStateEl.parentElement?.setAttribute(
       "aria-label",
-      state === "off" ? "Squelch off" : (state === "open" ? "Squelch open" : "Squelch closed"),
+      state === "off" ? "Squelch off" : (state === "open" ? "Squelch on, open" : "Squelch on, closed"),
     );
   }
   if (squelchLabelEl) squelchLabelEl.textContent = String(sdrSquelchThresholdDb);

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/spectrum-layout.mjs

@@ -144,12 +144,12 @@ try {
       shown: getComputedStyle(line).display !== "none",
       db: Number(document.getElementById("sdr-squelch-db").value),
       label: Number(document.getElementById("spectrum-squelch-label").textContent),
-      toggle: document.getElementById("sdr-squelch-toggle").textContent,
+      toggle: document.getElementById("sdr-squelch-toggle").getAttribute("aria-pressed"),
       top: Math.round(line.getBoundingClientRect().top),
     };
   });
   assert.equal(squelchOn.shown, true, "the threshold line did not appear with the squelch on");
-  assert.equal(squelchOn.toggle, "On", "the toggle did not follow the squelch state");
+  assert.equal(squelchOn.toggle, "true", "the SQL switch did not follow the squelch state");
   assert.equal(squelchOn.label, squelchOn.db, "the line and the readout disagree on the threshold");
 
   // Dragging the line down lowers the threshold and tells the server.