Keep the Radio tuning dial silent unless a stream is playing

Releasing the tuning dial always started the chosen station, plus tuning
static, even when nothing was playing. It now follows the Previous/Next
rule: the release plays only if a stream was loading, buffering or playing
when the drag began; otherwise it just selects the station.

The privacy note no longer lists finishing tuning as a way to connect and
now names voice instead, in all locales. Docs, changelog and comments are
tightened to match.

src/data/radio.test.mjs

@@ -902,12 +902,15 @@ test('failed exact tuner release cannot consume a stale playback fallback', asyn
     stations: stationRows,
     failingUrls: [stationRows[0].streamUrl],
   }, async ({ playUrls }) => {
-    assert.equal(radioLayer.selectStation(stationRows[0].id, { autoplay: false }), true);
+    // A playing stream, so the release plays.
+    assert.equal(radioLayer.selectStation(stationRows[1].id, { autoplay: true }), true);
+    await new Promise((resolve) => setTimeout(resolve));
     assert.equal(radioLayer.cycleStation(1, {
       stationIds: stationRows.map(({ id }) => id),
       autoplay: false,
       fallback: true,
     }), true, 'a voice-style prepared cycle creates the stale-fallback precondition');
+    playUrls.length = 0;
     assert.equal(radioLayer.beginTuning(), true);
     assert.equal(radioLayer.previewTuningStation(stationRows[0].id, { rotate: false }), true);
     assert.equal(radioLayer.commitTuningStation(stationRows[0].id, { origin: 'user' }).ok, true);

src/data/radioNextState.test.mjs

@@ -1,5 +1,4 @@
-// Radio Next/Previous that only select (autoplay: false), against the real layer
-// and the panel that renders it.
+// Radio selection, fallbacks and voice handoffs on the real layer and its published view.
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import { radioLayer } from './radio.js';
@@ -247,3 +246,28 @@ test('while a stream connects the transport buttons offer Pause, because a click
   assert.equal(shown.button, 'PAUSE');
   assert.equal(shown.cockpit, 'Ⅱ');
 });
+
+test('a dial release plays only if a stream was active when the drag began', async () => {
+  await withLayer([], async ({ playUrls }) => {
+    radioLayer.selectStation(ids[0], { autoplay: false });
+    assert.equal(radioLayer.beginTuning(), true);
+    radioLayer.previewTuningStation(ids[1], { rotate: false });
+    assert.equal(radioLayer.commitTuningStation(ids[1], { origin: 'user' }).ok, true);
+    await settle();
+    let state = radioLayer.getUIState();
+    assert.deepEqual(playUrls, []);
+    assert.equal(state.selected?.id, ids[1]);
+    assert.equal(state.audioState, 'stopped');
+    assert.equal(state.tuningStatic, false);
+
+    await radioLayer.togglePlayback({ origin: 'user' });
+    assert.equal(radioLayer.beginTuning(), true);
+    radioLayer.previewTuningStation(ids[2], { rotate: false });
+    radioLayer.commitTuningStation(ids[2], { origin: 'user' });
+    await settle();
+    state = radioLayer.getUIState();
+    assert.deepEqual(playUrls, [stations[1].streamUrl, stations[2].streamUrl]);
+    assert.equal(state.audioState, 'playing');
+    assert.equal(state.playingStationId, ids[2]);
+  });
+});