feat(globe): render the tilt and north-up buttons from the globe actions store

The camera orientation controls publish whether the map is tilted and the
camera's whole-degree heading instead of writing the buttons' attributes,
and answer tilt and north-up through the globe actions store. The new
GlobeCompass renders the heading, so a rotating camera re-renders only the
compass. The store drops an unchanged camera state and keeps each clear
owner's busy state, so the buttons show the shell that answers them: a
shell replaced by a newer one, or disposed mid-clear, leaves the live
shell's state alone, and an older shell that answers again shows its own.
createOwners gains owns() and ownerOf().

src/ui/stores/owners.test.mjs

@@ -33,3 +33,25 @@ test('act returns what the answering action returned', () => {
   assert.equal(act('pick', 'jazz'), 'kept jazz');
   assert.equal(act('missing'), undefined);
 });
+
+test('owns names the owner that answers an action', () => {
+  const { connect, detach, owns } = createOwners();
+  const older = connect({ tilt() {}, share() {} });
+  const newer = connect({ tilt() {} });
+  assert.equal(owns(newer, 'tilt'), true);
+  assert.equal(owns(older, 'tilt'), false);
+  assert.equal(owns(older, 'share'), true);
+  assert.equal(owns(newer, 'missing'), false);
+  assert.equal(owns(null, 'tilt'), false);
+  detach(newer);
+  assert.equal(owns(older, 'tilt'), true);
+});
+
+test('ownerOf names the token that answers an action', () => {
+  const { connect, ownerOf } = createOwners();
+  const older = connect({ clear() {}, share() {} });
+  const newer = connect({ clear() {} });
+  assert.equal(ownerOf('clear'), newer);
+  assert.equal(ownerOf('share'), older);
+  assert.equal(ownerOf('missing'), undefined);
+});