feat(street-level): Street View polish — name, filters, legend, marker

- The chip reads GOOGLE STREET VIEW (and its caption link likewise).
- Providers declare the imagery filters they honour (`filters`, default
  pano + since). Street View declares none: every panorama is 360° and it
  draws no coverage to thin, so its lookups ignore the filters and the
  panel hides IMAGERY and SINCE while it is the only lit provider.
- The legend lists only providers that draw coverage lines, with
  Selected only beside one: Street View alone shows no legend.
- Providers may pick their on-globe marker (`marker`); Street View's is a
  Google-blue field-of-view cone from a white-ringed dot, in place of
  GEV's amber pin, and switches back for a Mapillary photo.

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

CHANGELOG.md

@@ -102,7 +102,9 @@
   open Google's own panorama in
   the panel, with its arrows, the address and month in the caption, a link
   to Google Maps and FOLLOW. Share links carry it in the provider switches
-  (`r.google-1`).
+  (`r.google-1`). Its panoramas are all 360°, so the IMAGERY and SINCE
+  filters and the legend apply to Mapillary only and hide when GOOGLE STREET
+  VIEW is the only lit provider.
 
 - Add an experimental ChatGPT/Codex OAuth option for cloud voice in Provider
   Settings. API-key voice remains the default. Local sign-in can start from