``hr_timesheet_sheet`` ships a review workflow: the employee submits the sheet,
a reviewer approves or refuses it and may send it back to draft. Many
organisations never use it — they record hours and do not submit them for
approval.

The workflow is not harmless when it is not used. ``_check_state()`` forbids
modifying the timesheet entries of any sheet that is not in ``new`` or
``draft``. A sheet submitted by mistake and never attended freezes its entries
forever: nobody can edit them, and ``action_timesheet_draft()`` only works from
``done``, never from ``confirm``.

This module removes the review workflow from the user interface — buttons,
kanban actions, search filters, the department counter of sheets to approve
and the menus that only exist to serve it — and adds a wizard that sends the
sheets that got stuck in ``confirm`` or ``done`` back to draft.

The ``action_timesheet_*`` methods of the base module are left untouched, so
the rest of the family (``hr_timesheet_sheet_attendance``,
``hr_timesheet_sheet_policy_*``, ``hr_timesheet_sheet_autodraft``) keeps
working. They simply no longer have an entry point in the interface.