This update switches Odoo Enterprise styling to use variable fonts, helping simplify font management and improve consistency across screens. Users may notice more consistent text rendering in areas such as HR salary, referrals, knowledge, manufacturing reports, signing, social, and the main web interface.

Requires : 
- https://github.com/odoo/odoo/pull/100711

This draft update modernizes how form sections are laid out in Odoo Enterprise by replacing older table-based structures with more flexible grid layouts. The change supports the broader interface restyling effort and should make forms easier to maintain and adapt across screen sizes.

This PR replaces the FormView group tables with css grids.
Part of the overall v16 SCSS optimization/restyle, task-2704984

Requires:
- https://github.com/odoo/odoo/pull/98911

task-2918464

Spreadsheet filter editing now uses a newer field selection component instead of an older legacy widget. This keeps the spreadsheet experience aligned with current interface standards and should make future maintenance easier without changing core business workflows.

This revision replace the use of the legacy FieldSelectorWidget by the new component ModelFieldSelector.

Task-id 2987871