[6788][ADD] maintenance_equipment_inventory

[kanda999]

6788

[smorita7749]

Pushed f074ed1 to 18.0-add-maintnance_equipment_inventory (fixup, to be squashed).

Addresses review findings on the approval workflow and menu placement:

• Harden the approved-record lock. APPROVED_WRITABLE_FIELDS previously included state/approved_by_id/approved_date, which let any user with write access unlock an approved record via a raw write({"state": "draft"}) and then edit it freely — bypassing both the button groups and the action-method guard. The whitelist is now limited to message_main_attachment_id (the only field the mail framework writes without our allow_approved_write context). Workflow fields change only through the action methods, which set that context.
• Reset-to-draft permissions. A plain user can now pull a not-yet-approved (to_approve) record back to draft, while resetting an approved record stays manager-only. Implemented in both the method guard (action_reset_to_draft) and the form buttons (split into a non-restricted to_approve button and a manager-only approved button); the list-header button now relies on the method guard.
• Menu placement. The menu was parented under maintenance.menu_m_reports, a normally-hidden "Reporting" menu, which surfaced it and produced a duplicate "Reporting" top menu. Moved to maintenance.menu_maintenance_title (next to Equipment) — inventory records are operational data entry, not a report.
• Tests. Added regression tests: raw write cannot reset an approved record, a plain user may reset a to_approve record, and the approved-reset manager restriction.

Files:

models/maintenance_equipment_inventory_record.py      | 22 +++++++++++++-----
tests/test_maintenance_equipment_inventory_record.py  | 26 ++++++++++++++++++++++
views/maintenance_equipment_inventory_record_views.xml| 14 ++++++++----