Quantity Availability Is Now Calculated Per Booking Window

Booking quantity-tracked assets now asks the right question: how many units are free on your dates, rather than how many have ever been booked.

The difference matters most when stock is shared. A pool of 10 sandbags booked out 7 at a time in three different weeks needs only 7 at any one moment, so 3 stay free in each of those weeks. Shelf used to add all three together, decide 21 units were needed at once, show a negative Available on the asset page, and block check-out. The obvious escape, reducing the over-booked reservation, was rejected too, so the only way out was cancelling.

What changed:

• Dates are part of the count. A booking that ends before yours begins no longer competes with you. The exception is an overdue booking: nobody knows when a late return is coming back, so its units keep counting until it's checked in.
• The asset page separates now from later. Available is what's on the shelf right now. Units promised to future bookings sit on their own Reserved (bookings) row, so a reservation three weeks out no longer makes today's stock look smaller than it is.
• Lowering a quantity always works, whatever state the booking is in, so a booking that's short can be fixed rather than cancelled. Asking for more than the dates allow is refused with the exact shortfall.
• You'll be told when a booking falls short. A pool can shrink after a booking is confirmed, when a previous booking runs late or someone hands units out as custody. Instead of quietly cancelling, Shelf marks the booking with an amber Stock conflict pill on the bookings list and a red Insufficient stock badge on the item itself. A separate amber Checked out elsewhere badge is just a heads-up: those units are due back before your booking starts, or, on used-up stock, may be consumed at check-in instead of returned.
• Stock can't be pulled out from under a booking. Lowering an asset's total quantity below what's already promised to custody, kits, or overlapping bookings is now blocked.

Nothing needs fixing by hand. Pools that were showing a negative available figure resolve on their own.