The employee public form now includes a hidden header area that other HR apps can use to add buttons when needed. This makes it easier to extend the employee view without changing the base screen, and it remains invisible when no buttons are added.

Some modules might want to add buttons in the form header of the employee public
(e.g. hr_appraisal).
This commit adds an empty header to easily allow view inheritance.

Note: this empty header is not displayed if no buttons are indide.

Task 2028794
PR odoo/enterprise#6495


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The appraisal request flow is now simpler and more flexible, allowing managers and appraisal users to request reviews from employee records with clearer follow-up actions. Notifications now respect each recipient's Odoo communication preferences, and required recipients help prevent incomplete requests.

This PR mainly improves the flow and usability of the "request appraisal" wizard.

See commit messages for details

Task 2028794
PR #6495