Customers can now filter and sort their contracts directly from the website list view, making it easier to find the right contract quickly. The list also shows each contract's end date, and an incorrect cancelled-state reference was corrected to match the actual contract status.

task: https://www.odoo.com/web#id=26636&view_type=form&model=project.task&action=327&menu_id=4720
pad: https://pad.odoo.com/p/r.3711bf1fe2aed8bc3b116dab7ac8f0f0

This change simplifies how Odoo keeps view reference information up to date, reducing the chance of stale or incorrect data. It preserves the ability to find views by reference while avoiding unnecessary stored data, making maintenance more reliable.

This simplifies the fix for recomputing that field in a much better way than #13885.
The field was stored for the sake of searching; instead we implemented a search
method for it.