fix(ui): SAR credential setup in Settings and async layer toggles.

Add Earthdata token entry on the SAR tab with accurate Mode B status, expose optional FIRMS_MAP_KEY in API settings, and remove the frontend operator-unlock gate that blocked localhost saves. Run network-heavy layer-enable fetches on a background executor with frontend retry polling so FIRMS toggles no longer freeze the single API worker.

backend/tests/test_layer_enable_integration.py

@@ -1,6 +1,8 @@
 """Integration: layer enable triggers immediate data availability."""
 from __future__ import annotations
 
+import time
+
 from services.fetchers._store import active_layers, latest_data, _data_lock
 
 
@@ -12,7 +14,13 @@ def test_firms_enable_populates_slow_payload(client):
     r = client.post("/api/layers", json={"layers": {"firms": True}})
     assert r.status_code == 200
 
-    slow = client.get("/api/live-data/slow")
-    assert slow.status_code == 200
-    fires = slow.json().get("firms_fires") or []
-    assert len(fires) > 0, "firms layer should populate on enable without waiting for scheduler"
+    fires: list = []
+    for _ in range(45):
+        slow = client.get("/api/live-data/slow")
+        assert slow.status_code == 200
+        fires = slow.json().get("firms_fires") or []
+        if fires:
+            break
+        time.sleep(2)
+
+    assert len(fires) > 0, "firms layer should populate after async on-enable fetch"