feat(bikeshare): add Oslo, Bergen and Trondheim Bysykkel

Add Norway's three Urban Sharing city-bike systems to the Bike Share
layer and get_bike_share. The feeds are keyless GBFS on
gbfs.urbansharing.com, which joins the proxy allowlist. The proxy now
sends the Client-Identifier header the operators ask clients to send.
Attributed under NLOD 2.0 in DATA_SOURCES.md and the data credits.

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

src/data/dataCredits.js

@@ -251,6 +251,13 @@ export const DATA_CREDITS = [
     key: 'gbfs',
     html: 'Bikeshare availability: GBFS operator feeds (e.g. Austin BCycle)',
   },
+  {
+    key: 'urbansharing-gbfs',
+    html:
+      'City bikes (Norway): contains data under the ' +
+      '<a href="https://data.norge.no/nlod/en/2.0" target="_blank" rel="noopener">Norwegian licence for Open Government data (NLOD)</a> ' +
+      'made available by Oslo Bysykkel, Bergen Bysykkel and Trondheim Bysykkel',
+  },
   {
     key: 'osrm-routing',
     // The service asks for its attribution to carry a "fix the map" link, so