[fix](trx-frontend-http): stop the browser offering saved values for frequency

The tuned and centre frequency readouts are text inputs, so the browser
keeps what has been typed into them and offers it back in a dropdown --
Edge does this out of the box, dropping stale frequencies from other
sessions over the reading.

Turn autofill off on both, along with autocorrect and spellcheck, which
have no business near a number either.

Fixes #39

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

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

@@ -209,11 +209,11 @@ SPDX-License-Identifier: GPL-2.0-or-later
             <div class="label"><span>Signal strength</span></div>
           </div>
           <div class="freq-field frequency-col">
-            <input class="status-input" id="freq" type="text" value="--" aria-describedby="freq-label" aria-label="Tuned frequency" />
+            <input class="status-input" id="freq" type="text" value="--" aria-describedby="freq-label" aria-label="Tuned frequency" autocomplete="off" autocorrect="off" spellcheck="false" />
             <div class="label" id="freq-label"><span>Frequency</span></div>
           </div>
           <div class="freq-field frequency-col center-frequency-col" id="center-freq-field" style="display:none;">
-            <input class="status-input" id="center-freq" type="text" value="--" aria-describedby="center-freq-label" aria-label="SDR center frequency" />
+            <input class="status-input" id="center-freq" type="text" value="--" aria-describedby="center-freq-label" aria-label="SDR center frequency" autocomplete="off" autocorrect="off" spellcheck="false" />
             <div class="label" id="center-freq-label"><span>Center Frequency</span></div>
           </div>
         </div>

src/trx-client/trx-frontend/trx-frontend-http/frontend/tests/browser-smoke.mjs

@@ -376,6 +376,18 @@ try {
     `text grew without a resize and the strip overlaps by ${unresized.overlap}px`);
   assert.equal(unresized.iconsOnly, true, "the strip kept its labels with no room for them");
 
+  // The frequency readouts are typed into, so the browser remembers what went
+  // in and offers it back in a dropdown over the reading — Edge does this by
+  // default. Nothing here wants to be autofilled from what was tuned last week.
+  const autofill = await page.evaluate(() => ["freq", "center-freq"].map((id) => {
+    const input = document.getElementById(id);
+    return { id, autocomplete: input?.getAttribute("autocomplete") ?? null };
+  }));
+  for (const field of autofill) {
+    assert.equal(field.autocomplete, "off",
+      `#${field.id} offers autofill (autocomplete=${field.autocomplete})`);
+  }
+
 } finally {
   await browser.close();
   await fixture.close();