Work Items - Lock

Problem

You can lock an issue. We'll need to support this for work items.

Proposal

Lock behavior should mirror existing behavior on Issues and MRs. As of !135754 (merged) all references should be to lock discussion of the object, rather than locking the object itself.

Criteria	Reference	Note
Lock/unlock action in actions menu		Always "Lock discussion" Uses loading state when transitioning states
Toast on successful state change		"Discussion <locked|unlocked>."
Lock badge in header area		orange-100 badge with orange-700 icon lock Badge appears only when locked (no unlocked badge state) Show tooltip "The discussion in this <object type> is locked. Only project members can comment." on hover
Lock badge in activity area (project member)		If locked, not confidential, show locked warning If both locked and confidential, show combination warning. Only show comment box if user is still able to comment (e.g. not locked out)
Lock badge in activity area (non-project member)		No comment box (user is locked out of discussion)