feat(radio): answer the RTL-SDR card through the radio store

SdrCard calls LocalSdrControls through radio store actions instead of
DOM listeners, and renders its gain options from the receiver's own
R820T gain steps with page-language labels. The display and radio
stores share one owner list (createOwners): the newest connected owner
with an action answers it.

src/ui/sdrCardActions.test.mjs

@@ -0,0 +1,97 @@
+// src/ui/sdrCardActions.test.mjs — the local RTL-SDR card's controls call
+// LocalSdrControls through the radio store, and its gain options read in the
+// page language with numeric values.
+import '../testSupport/registerDom.mjs';
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { createApp } from 'vue';
+import { createPinia } from 'pinia';
+import { localSdrGainOptionLabel } from './localSdrPresentation.js';
+import { useRadioStore } from './stores/radio.js';
+import SdrCard from './views/panels/SdrCard.vue';
+
+function mount(t) {
+  document.body.replaceChildren();
+  const pinia = createPinia();
+  const store = useRadioStore(pinia);
+  const calls = [];
+  store.connect(
+    new Proxy(
+      {},
+      {
+        get:
+          (_, name) =>
+          (...args) =>
+            calls.push([name, ...args]),
+      },
+    ),
+  );
+  const app = createApp(SdrCard).use(pinia);
+  app.mount(document.body.appendChild(document.createElement('div')));
+  t.after(() => app.unmount());
+  return calls;
+}
+const $ = (id) => document.getElementById(id);
+const fire = (el, type, init) =>
+  el.dispatchEvent(
+    type === 'keydown'
+      ? new KeyboardEvent(type, { bubbles: true, cancelable: true, ...init })
+      : new Event(type, { bubbles: true }),
+  );
+
+test('the card’s buttons, gain, tuning and volume call LocalSdrControls', (t) => {
+  const calls = mount(t);
+  for (const id of [
+    'sdr-connect-btn',
+    'sdr-locate-btn',
+    'sdr-change-device-btn',
+    'sdr-mode-fm-btn',
+    'sdr-mode-adsb-btn',
+  ])
+    $(id).click();
+  $('sdr-gain-select').value = '20.7';
+  fire($('sdr-gain-select'), 'change');
+  $('sdr-frequency-input').value = '101.1';
+  $('sdr-tune-btn').click();
+  $('sdr-frequency-input').value = '95.3';
+  const enter = fire($('sdr-frequency-input'), 'keydown', { key: 'Enter' });
+  fire($('sdr-frequency-input'), 'keydown', { key: 'a' });
+  $('sdr-volume').value = '40';
+  fire($('sdr-volume'), 'input');
+  assert.equal(enter, false, 'Enter is taken by the tune');
+  assert.deepEqual(calls, [
+    ['toggleSdrConnection'],
+    ['locateSdr'],
+    ['changeSdrDevice'],
+    ['setSdrMode', 'fm'],
+    ['setSdrMode', 'adsb'],
+    ['setSdrGain', '20.7'],
+    ['tuneSdr', '101.1'],
+    ['tuneSdr', '95.3'],
+    ['setSdrVolume', '40'],
+  ]);
+});
+
+test('the seek buttons step down and up', (t) => {
+  const calls = mount(t);
+  for (const id of ['sdr-seek-back-btn', 'sdr-seek-forward-btn']) {
+    $(id).disabled = false;
+    $(id).click();
+  }
+  assert.deepEqual(calls, [
+    ['seekSdr', -1],
+    ['seekSdr', 1],
+  ]);
+});
+
+test('gain options keep numeric values and read as decibels', (t) => {
+  mount(t);
+  const options = [...$('sdr-gain-select').options];
+  assert.equal(options.length, 30);
+  assert.equal(options[0].value, 'auto');
+  assert.equal(options[2].value, '0.9');
+  assert.equal(options[2].textContent, localSdrGainOptionLabel('0.9'));
+  assert.match(options[2].textContent, /^0\.9\sdB$/u);
+  assert.equal(options[2].getAttribute('translate'), 'no');
+  assert.equal(options.at(-1).value, '49.6');
+});