Ease a late zoomed tilt to its new limit instead of jumping there

From 400 km, a tilt to -5° that a zoom out x2.5 caught at -8.0005° reported -8°, and the next frame jumped to -9.407° and ended there. The zoom kept the camera's pitch as the goal when it was already past the new range's horizon limit, but at the same pivot pitch the longer range looks down more steeply, so the next lookAt dropped the camera 1.4° at once.

The zoom now re-solves the pivot pitch so the new range keeps the camera's pitch, and aims the tilt at the asked angle or the new limit, even when that limit is below where the camera stands: the tilt eases down to it. The zoom's reply names that end, and the camera reaches it with no frame moving more than 0.1°.

src/cameraTilt.test.mjs

@@ -686,3 +686,32 @@ test('a voice zoom during a tilt to an angle passes on the new end angle', async
   );
   assert.match(zoom.note, /horizon/);
 });
+
+// Late in the tilt the camera is already past the angle the new range's
+// horizon allows (from 400 km at -8°, a zoom out x2.5 reported -8° and the
+// next frame jumped to -9.4°): it eases to that limit with no jump, and the
+// zoom's reply names the angle it ends at, not the one it stood at.
+test('a late zoom out during a tilt eases to the new limit and reports it', (t) => {
+  const h = harness(t, { height: 400_000 });
+  moveCamera({ motion: 'tilt', pitchDeg: -5 });
+  for (let i = 0; i < 70; i += 1) h.tick();
+  const zoom = adjustOrbitRange(2.5);
+  assert.equal(zoom.changed, true);
+  let last = pitchDeg(h.camera);
+  let maxStep = 0;
+  for (let i = 0; i < 600 && getActiveCameraMotion(); i += 1) {
+    h.tick();
+    maxStep = Math.max(maxStep, Math.abs(pitchDeg(h.camera) - last));
+    last = pitchDeg(h.camera);
+  }
+  assert.equal(getActiveCameraMotion(), null, 'tilt must finish');
+  assert.ok(maxStep < 0.5, `pitch jumped ${maxStep}° in one frame`);
+  assert.ok(h.viewTarget(), 'the crosshair is on the sky');
+  // Replies give whole degrees: the reported angle is the reached one rounded.
+  assert.equal(
+    zoom.pitchDeg,
+    Math.round(pitchDeg(h.camera)),
+    `camera at ${pitchDeg(h.camera)}°, zoom reported ${zoom.pitchDeg}°`,
+  );
+  assert.match(zoom.note, /horizon/);
+});