Round-Robin Reservation Locks Slot for All Hosts

[husniabad]

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Issue Summary

Round-Robin event slots disappear completely after first reservation instead of remaining available for additional bookings up to host capacity. When Round-Robin events share hosts, any single reservation blocks the entire time slot across all event types, preventing proper capacity utilization.

Steps to Reproduce

1. Create 2 Round-Robin event types with same 2 hosts for each
2. Navigate to booking page and select any time slot
3. Make a reservation for that slot
4. Refresh page or check from different browser
5. Observe the same time slot is no longer available
6. This occurs whether using single or multiple event types that share the same hosts.

Actual Results

• Time slots completely disappear after first reservation
• Round-Robin events behave like Collective events (all-or-nothing) while reserving
• Shared host capacity is not properly calculated across reservations
• Users cannot make additional bookings for same time slot

Expected Results

• Slots should remain available until all hosts are booked (e.g., 2 reservations for 2 hosts)
• Round-Robin should allow multiple reservations per time slot up to host capacity
• Proper capacity-based availability calculation across shared hosts

Evidence

• Created test scenario with 2 different Round-Robin events using same 2 hosts. After making first reservation, verified in database that only 1 reservation exists but time slot disappeared completely for that event and other events.
• Expected behavior: slot should remain available for second booking. Issue occurs due to incorrect reservation filtering logic that doesn't properly handle Round-Robin capacity calculation.

[linear]

CAL-6592