Helpdesk users and customers get a clearer ticket experience with an improved portal sidebar, better ticket lists, new filters, and easier access to related records like sales orders, tasks, credit notes, and forum posts. The update also improves SLA visibility based on sales confirmation timing and adds better activity tracking, helping teams manage support work with more context and less navigation.

The purpose of the commit is to do several usability improvements and add some new features.

So in this commit, we did several usability improvements and added the below feature:
- revamp the portal with a portal sidebar
- added SLA validity on product based on so confirmation date
- helpdesk overview added the list view with the user dashboard.

task-2722488

Website managers can now work with the current website inside a backend iframe, with updated menus and dialogs for creating content such as appointments. This streamlines editing workflows, removes older website toolbar pieces, and aligns related website apps with the new experience.

task-2687506

An unused styling file was removed from the Snailmail Account Follow-up module because it was incorrectly referenced and its rule was not being applied. This is a small cleanup that reduces unnecessary code without changing expected user behavior.

This commit removes the unused `snailmail_account_reports_followup_asset.scss`
file.

Actually, this file was wrongly referenced in the assets bundle since
commit odoo/enterprise@267123d4b758a87607f9023d347c478bbfbcef77 and, thus the single CSS
rule concerned wasn't applied.

Co-authored-by: Romeo Fragomeli <rfr@odoo.com>

This update enriches the Belgian payroll accounting test setup by adding employee skill history information. It helps ensure payroll-related processes are tested with more complete and realistic employee data, reducing the risk of gaps in future changes.