Add equipment management to events

- Add equipmentProvided and requiredItems fields to Event model
- Update event creation form with equipment section
- Allow organizers to specify if equipment is provided or BYO
- Display required items list in event details
- Update database schema and run migration

server/prisma/schema.prisma

@@ -83,6 +83,8 @@ model Event {
   participantCount Int?                 @default(0) @map("participant_count")
   litterCollected  Decimal?             @map("litter_collected") @db.Decimal(10, 2)
   photos           Json?
+  equipmentProvided Boolean?            @default(false) @map("equipment_provided")
+  requiredItems    Json?                @map("required_items")
   createdAt        DateTime?            @default(now()) @map("created_at") @db.Timestamp(0)
   updatedAt        DateTime?            @default(now()) @updatedAt @map("updated_at") @db.Timestamp(0)
   registrations    EventRegistration[]