Strict adherence to canonical ActivityNames, to avoid the problem where Spothole was giving out activities like ["Towers", "TOWERS"]. All uses of ActivityName should now be canonical not arbitrary strings, and attempts to convert unknown strings to activitynames will be logged for me to check out.

data/activity_ref.py

@@ -1,6 +1,6 @@
 from dataclasses import dataclass
 
-from core.enums import ActivityRefType
+from core.enums import ActivityName, ActivityRefType
 
 
 @dataclass
@@ -9,7 +9,7 @@ class ActivityRef:
     name and a lookup URL."""
 
     # Activity that this reference is in, e.g. "POTA".
-    activity: str
+    activity: ActivityName
     # Reference ID, e.g. "GB-0001".
     id: str | None = None
     # Name of the reference, e.g. "Null Country Park", if known.