contact-us: unify flow across group walks and group events with per-type config (#222)
Rename WalkLeaderContactMethod enum to EventLeaderContactMethod
Add separate groupWalkContact* and groupEventContact* config fields
to Organisation, with backward-compat fallback to legacy walkLeaderContact* fields
Create EventContactService that inspects event item_type to select
the correct config block and build the correct event URL
Rewire EventLeaderContactLinkComponent to use EventContactService
instead of WalkDisplayService for event-type-aware contact behaviour
Update admin System Settings UI with two contact sections:
Group Walk Contact Method and Group Event Contact Method
Fix walk card visibility for logged-out users by adding difficulty,
distance, ascent, status, contactDetails and other fields to the
public API field selection in LocalWalksAndEventsService