feat: Wildlife Sightings layer from iNaturalist and Acartia

Recent community wildlife observations, as a new Wildlife group in the
layer panel.

- Server: keyless iNaturalist proxy (v2 observations with only the
  projected fields; undocumented v1 UTFGrid density tiles, decoded on the
  server) sharing one paced queue (burst 4, ~1/s, 60/min, 8,000/day budget,
  up to four in flight), in-memory caches and upstream-only cooldowns;
  Acartia Salish Sea marine-mammal feed rounded to 0.01 degrees with
  comments dropped.
- Layer: grid counts drawn as a soft view-ranked density glow; real sampled
  sightings as taxon badges at their true positions with ambient photo
  thumbnails and labels; obscured records stay privacy cells; a clicked
  sighting stays pinned through camera moves and refreshes.
- Anchored photo card per selection with the single iNaturalist link;
  attribution in the layer row and the Data attribution popover.
- Filters (CONFIRMED, taxa presets) round-trip in share links with token 9.

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

src/data/dataCredits.js

@@ -34,6 +34,14 @@ export const OPENMAPTILES_CREDIT = {
   html: 'Vector tiles: <a href="https://openfreemap.org" target="_blank" rel="noopener">OpenFreeMap</a> © <a href="https://openmaptiles.org" target="_blank" rel="noopener">OpenMapTiles</a>',
 };
 
+/** Conditional Salish Sea coverage; registered when its sightings first render. */
+export const ACARTIA_CREDIT = Object.freeze({
+  key: 'acartia',
+  html:
+    'Wildlife sightings: <a href="https://acartia.io" target="_blank" rel="noopener">Acartia</a> (CC BY 4.0; each provider credited per sighting) · ' +
+    '<a href="https://www.bewhalewise.org" target="_blank" rel="noopener">Be Whale Wise</a>',
+});
+
 const osmDisplays = new WeakMap();
 
 function updateOsmDisplay(viewer, state) {
@@ -188,6 +196,10 @@ export const DATA_CREDITS = [
       '<a href="https://adds-faa.opendata.arcgis.com/" target="_blank" rel="noopener">FAA Special Use Airspace</a>' +
       ' (prohibited and restricted zones; informational only)',
   },
+  {
+    key: 'inaturalist',
+    html: 'Wildlife sightings: <a href="https://www.inaturalist.org" target="_blank" rel="noopener">iNaturalist</a> contributors (licences per record; photos credited on each card)',
+  },
   OSM_CREDIT,
   OPENMAPTILES_CREDIT,
   {