Partner Stage - Display only confirmed partners

This module works together with the partner stage feature. It changes how partner selection fields behave on form screens.

• On any form, every field that links to a partner (res.partner) is automatically limited to partners whose stage is confirmed. This applies to all models, not just one screen.
• If a field already had its own filter, the confirmed-partner condition is added to it, so both rules apply together.
• The filtering is on by default when the module is installed.
• You can switch it off for a specific screen by passing a context value, or globally by setting the system parameter partner_stage.only_confirmed_partners to a false-like value such as False, false, empty, or 0.
• The module does not add menus, buttons, or reports. It only adjusts the partner search filters used by form views.
• It touches the base view-building mechanism (base model) and relies on the partner stage module for the confirmed state.