fix(wildlife): point the Acartia card link only at acartia.io

The card's "Acartia" link was built from the contributor-supplied
photo_url, so any https site could appear labelled as Acartia. Acartia
has no documented per-sighting page, so the source link is now always
the Acartia site, on the server projection and again in the card.
The separate "Open on Acartia" fallback link is no longer needed.

docs/CURRENT-STATE.md

@@ -174,7 +174,8 @@ compact anchored photo card. Selection stays pinned across camera, filter and
 sample changes until explicit deselection or layer disable. Its medium image
 uses `object-fit: contain`, with names, compact observed age and creator/licence.
 The card is the single source link to iNaturalist. Obscured sightings also stay
-text-only; Acartia stays text-only with provider credit and whale guidance.
+text-only; Acartia stays text-only with provider credit and whale guidance,
+and its source link is always `https://acartia.io/`, never a contributed URL.
 Placement avoids actual HUD, toolbar and rail rectangles, panning only when
 necessary while preserving zoom. Escape, close or an outside click closes the
 card and clears selection. Camera/layout changes reposition the card without