fix(street-level): review fixes for show_street_level and sl= links

P1: on a phone the Street Level panel sits in the Cameras tab sheet, so the
action and sl= links opened photos nobody could see and still reported
success. A photo that opens, and a link that arms, now open that sheet
(revealPanel). In cockpit, clean view, recording or scene playback the action
stops at a new `view` stage before anything switches or loads.

P2s:
- Mapillary's nearest search asks for 100 photos, the API's most. It cuts
  the radius's photos at the limit in no particular order, so 8 left the
  distance sort and the imagery filter a few arbitrary photos.
- The MCP globe panel opens a billed photo only for a result issued in the
  last five minutes (show_in_gods_eye_view stamps issued_at); a host that
  mounts the panel again hands back the old result, which only arms.
- OPEN uses an armed link's point only while the view centre is within 1 km
  of it; a user who moved on opens what the view shows.
- show_in_gods_eye_view measures a camera's altitude from the terrain under
  it before taking its look-at point, so high cities no longer put the
  photos kilometres too far ahead.
- The armed-link toast is translated, and the new view-stage message too,
  in all 11 catalogs.
- Tests: a turn superseded during the geocode, flight or map switch changes
  nothing; an unknown key state lets a cold sl= link through; a wide tilted
  area still opens photos at its centre.

changelog.d/1113-show-street-level.md

@@ -6,7 +6,14 @@
   `show_in_gods_eye_view` and a link can open a panorama at a place. Street
   View lookups from a geocoded place search up to 250 m; clicks keep 50 m. A
   plain link with `sl=google` arms Street View and leaves the billed load to a
-  press of OPEN GOOGLE STREET VIEW; embedded views open it. The source the
+  press of OPEN GOOGLE STREET VIEW, which aims at the view centre again once
+  the visitor has moved more than 1 km away; embedded views open it, and the
+  God's Eye View panel only for a result issued in the last five minutes. On
+  a phone, a photo that opens or a link that arms opens the Cameras sheet;
+  in cockpit, clean view, recording or scene playback the action says the
+  panel is hidden instead of loading a photo nobody sees. Mapillary's
+  nearest-photo search asks for 100 photos, so the nearest and the filter's
+  pick come from the spot's photos rather than an arbitrary eight. The source the
   action lights stays lit like a chip click. An unavailable map stack now
   reports the controller's own reason instead of always asking for a Cesium
   ion token. When nothing is found and a 360°, flat or SINCE filter the source