Adds a rule-based system to determine participant status in CREATE
payloads. Participants selecting a 'Begleitperson' service now receive
status 'O' (Option), all others default to 'F' (Final).
- Add ParticipantStatusRuleInterface for defining status rules
- Add ParticipantStatusRuleRegistry for priority-based rule evaluation
- Add ChaperonServiceStatusRule for Begleitperson detection
- Integrate status evaluation into BookingPayloadBuilder
Björn Fromme