Street Level: polar look-at, a bounded terrain wait, takeovers during the flight

- The look-at longitude wraps fully, so a tilted camera at a pole gives a
  point on the globe. The strict off-globe check on street_level is undone:
  points are clamped again, as before.
- A posted view that fails is answered, and the views behind it still apply.
- A posted view waits at most 2 s for the terrain under its camera, then
  keeps its own estimate.
- A camera taken during that wait stays where it is: the rest of the view
  applies, and only its photos stand down.
- show_street_level keeps a search or a press on the globe made during its
  own flight: it adopts only its own navigation stamps on landing, and a
  gesture is never forgiven.

docs/CURRENT-STATE.md

@@ -5323,7 +5323,9 @@ another map; `street_level` does not combine with `follow`.
 `show_in_gods_eye_view`, and the embedded app for a posted view with no
 point, measure the view's altitude from the terrain under the camera
 (`groundedLookAt` with the terrain heights service) before taking the look-at
-point, and keep the view's own estimate without a terrain answer. Links carry
+point, and keep the view's own estimate without a terrain answer (the embedded
+app waits 2 s for one). A camera taken during that wait stays where it is:
+the rest of the view applies and its photos do not open. Links carry
 `sl=<source>,<lat>,<lon>`; the globe panel applies views through the action,
 and a plain link runs it once restored (one shot: the rewritten hash drops
 `sl`). A link that follows an entity ignores `sl`.