3.5 Move, resize and reschedule

• Drag a booking on the grid to change the time; drag to another column to change the professional / service / space.
• Resize from the edge (bottom on the grid, right on the Gantt) to change the duration.
• Each change asks for confirmation and is validated (hours, conflicts, staff schedule, capacity/exclusivity of spaces). If invalid, it's rejected with a message.
• On rescheduling, the customer is notified ("Changed") and the reminder is re-armed.

On mobile: press and hold ~0.3 s on the booking until it "lifts" (vibrates) before dragging/resizing — so you don't move it by accident while scrolling. A quick tap opens Details.

📸 03-drag.png — A booking being dragged to another column/time, with the confirm modal.