Add SCEvents visibility and edit-access handling

[trista-chen-29]

Closes #2082

Changes

• Added status, visibility, and minimum_visible_role fields to:
  • Create Event page
  • Edit Event page
• Added frontend filtering for SCEvents event cards based on:
  • draft vs published
  • public vs private
  • minimum visible role
• Kept edit access aligned with the current SCEvents backend:
  • only event admins can edit events

Current visibility behavior

User type	Published + Public	Published + Private (member)	Published + Private (officer)	Draft
Non-member	✅	❌	❌	❌
Member	✅	✅	❌	❌
Officer (not event admin)	✅	✅	✅	❌
Event admin	✅	✅	✅	✅
Admin	✅	✅	✅	✅

Current edit behavior

User type	Can edit event
Non-member	❌
Member	❌
Officer (not event admin)	❌
Event admin	✅
Admin (not event admin)	❌

Verification

• feature flag OFF

• feature flag ON
  • Public / Non-member
    Only public published events are visible

• Member

• Officer (event creator)
  Draft event is visible and editable

• Another officer (not event admin)

• Admin

Draft event is visible, but edit is restricted to event admins

[steeevin88]

awesome stuff