Summary: Add the ability to schedule a room move before check-in within a single reservation. This would support a planned “réservation en escalier” without requiring the property to create multiple consecutive reservations for the same guest.

Problem: When a property already knows before arrival that a guest must change rooms during the stay, the current workaround is to create separate reservations for each room period. For example, a three-room itinerary may require three linked reservations. This creates unnecessary administrative work and increases the risk of:
- Fragmented guest and reservation records
- Manual handovers between reservations
- Confusion for front-office and housekeeping teams

Proposed solution: Keep the existing reservation process unchanged, but allow the reservation’s room assignment to be divided across multiple date ranges before check-in.

For example:
The guest has one reservation for seven nights.
The first four nights are assigned to room 201.
The final three nights are assigned to room 303.
The reservation remains a single guest stay and is not split into separate reservations.

The planned room move should be visible on the planning board and in the reservation details. The user should be able to move only part of the reservation to another room by selecting the relevant nights.

A clear action, such as Confirm room move, should then formalize the planned change and update the operational room assignment. This would provide an explicit “top” indicating that the guest will move from room 201 to room 303 during the stay.

User story: As a hotel staff member, I want to assign different rooms to different periods of one reservation before check-in, so that I can prepare a planned room move without creating multiple reservations for the same guest.