refactor(street-level): trim dead paths, duplicated labels and test-only API

- visibleBbox: no view-rectangle fallback or grid option; its one caller
  always ranges the rays
- tilesForBbox returns the tiles; normalizeBbox takes arrays only
- viewerHost: no try/catch around adapter calls that catch for themselves
- coverage: counts come from the drawn sequences; no sequenceCount export
- one keyStatusLabel for the pill and the layer list
- no constructor source check, double-init guard or selectSequence /
  clearSequence on the layer

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/ui/streetLevelPresentation.js

@@ -1,4 +1,5 @@
 import { keySetupRequirement } from '../keySetupCore.mjs';
+import { keyStatusLabel } from '../layers/streetLevel/policy.js';
 
 // Street Level UI state to panel strings and flags. Pure, so it is testable.
 
@@ -59,10 +60,8 @@ const drawing = (state) => state.enabled === true && state.providerOn !== false;
 function presentStatus(state) {
   const pressed = drawing(state);
   const title = pressed ? 'Turn Street Level off' : 'Turn Street Level on';
-  if (state.keyRejected)
-    return { text: 'KEY REJECTED', tone: 'warn', pressed, title };
-  if (state.keyRequired)
-    return { text: 'KEY REQUIRED', tone: 'warn', pressed, title };
+  const key = keyStatusLabel(state);
+  if (key) return { text: key, tone: 'warn', pressed, title };
   if (state.coverage.loading)
     return { text: 'LOADING', tone: 'busy', pressed, title };
   return pressed