fix(transit): show a reported 359.6° bearing as hdg 0°, not hdg 360°

The selected-vehicle card rounded the operator's reported bearing without
wrapping, so a GTFS-Realtime vehicle heading 359.5° or more read
"reported hdg 360°". The card now wraps after rounding: 359.6° reads
"reported hdg 0°", 359.4° still reads "reported hdg 359°".

src/layers/transit/policy.js

@@ -405,9 +405,12 @@ export function buildTransitSelectionCopy(
     reportedMotion.push(
       t('reported {speed} km/h', { speed: Math.round(record.speedMps * 3.6) }),
     );
+  // 359.5° and above rounds to north; modulo keeps it from printing 360°.
   if (Number.isFinite(record.bearing))
     reportedMotion.push(
-      t('reported hdg {heading}°', { heading: Math.round(record.bearing) }),
+      t('reported hdg {heading}°', {
+        heading: Math.round(record.bearing) % 360,
+      }),
     );
   // The operator's own claim, kept as a REPORT rather than as the live state.
   // It describes the moment of the report, which the display may not have

src/layers/transit/vocabulary.test.mjs

@@ -43,6 +43,18 @@ test('the selection card calls a Toronto 501 a streetcar', () => {
   assert.doesNotMatch(copy.details.join(' | '), /Tram/);
 });
 
+test('the selection card reads a bearing that rounds to north as hdg 0°', () => {
+  const hdg = (bearing) =>
+    buildTransitSelectionCopy(
+      ttc(),
+      { id: '4400', routeId: '501', timestamp: 0, bearing },
+      'tram',
+      0,
+    ).details.find((line) => line.includes('hdg'));
+  assert.equal(hdg(359.4), 'reported hdg 359°');
+  assert.equal(hdg(359.6), 'reported hdg 0°');
+});
+
 test('detection labels carry the operator vocabulary within the field width', () => {
   const klass = transitDetectionClass('tram', ttc());
   assert.equal(klass, 'STREETCAR TTC');