Say why Transit and Bike Share rows are empty outside coverage

Over a city with no feed or system (London, Tokyo) both rows read
"ON · — · never", the same as a feed that never answered. Transit already
computed a coverage note but put it only in `coverage`, which the row does
not show; Bike Share reported nothing at all.

Both layers now report a `zoom-in` guidance status with a `statusMessage`:
"Fly below 3,000 km to a covered region" / "No feed here yet · N regions
available" for Transit, and "Fly below 48 km to a covered city" / "No bike
share here yet · N systems available" for Bike Share. A loading or failed
Bike Share city keeps its own text. Leaving coverage clears the layer's
last-update time, so the row no longer dates data it no longer draws.

The coverage-note translations move from the voice card into
`translateStatusMessage` (ui/statusText.js), which the Layers row and the
voice card now share.

docs/CURRENT-STATE.md

@@ -1817,6 +1817,19 @@ Mapped-installation zoom guidance appears in the layer row without counting as
 a global loading failure. Guidance statuses do not suppress independent refresh
 errors.
 
+Transit and Bike Share report the same kind of guidance when no feed or system
+covers the view, instead of an undated `never`. Above their altitude gates the
+rows read `GTFS-RT · Fly below 3,000 km to a covered region` and
+`GBFS · Fly below 48 km to a covered city`; lower down over a city neither
+covers (London, Tokyo) they read `GTFS-RT · No feed here yet · N regions
+available` and `GBFS · No bike share here yet · N systems available`, N being
+the enabled feeds and the catalogued systems. The
+chip stays ON. A Bike Share city that is loading or failed keeps its own
+loading or error text. Leaving every covered feed or system clears the layer's
+last-update time, so the row never dates data it no longer draws. The same
+English notes are the voice analyst's empty-result notes; both surfaces show
+them translated through `translateStatusMessage` (`src/ui/statusText.js`).
+
 ## Places and CCTV request bounds
 
 With a Google key configured, nearby and text search reject missing, blank,