This change clears the blackbox processing queue whenever point-of-sale data is reloaded. It helps prevent rare situations where queued requests could keep repeating and cause the POS to become unresponsive.

This commit adds a clear of the blackbox queue when reloading data. This could avoid potential unexpected deadloop of calls in the queue.

Forward-Port-Of: odoo/enterprise#99252

This change removes the need for the Sign app to be installed for the accountant knowledge features to work. It simplifies setup and reduces unnecessary dependency between products, while keeping the related templates and embedded signature elements available where needed.

task-5154292

The point-of-sale now shows clearer guidance when the fiscal device is disconnected or when a social security number is required but missing. This helps staff quickly understand what went wrong and what action to take, reducing delays at checkout.

We now display an error when the FDM is disconnected, or when the user needs to fill in the social security number.
We also advise what to do in such cases.

Forward-Port-Of: odoo/enterprise#99319
Forward-Port-Of: odoo/enterprise#99285