Reinstate recentchanges_view POST handler

[jimchamp]

Closes #11894

Restores the recentchanges_view POST handler, which was thought to be unused. Authentication is now required for this endpoint. Usage is restricted to admins and super-librarians.

Technical

Testing

Screenshot

Stakeholders

[Copilot]

Pull request overview

Restores the recentchanges_view POST handler used by the Recent Changes UI to “Undo All” (e.g., undoing merges), adding authentication and restricting access to admins and super-librarians.

Changes:

• Add recentchanges_view.POST handler to perform an undo and redirect back to the change page
• Require a logged-in user and membership in admin/super-librarians usergroups for this endpoint
• Gate undo behind the undo feature flag

[Copilot]

The inline comment # TODO: unused import? is inaccurate here: safeint is used later in this module (e.g., for limit/offset parsing). Please remove or update the comment to avoid misleading future cleanup.

Suggested change

	) # TODO: unused import?
	)

[Copilot]

Consider moving allowed_usergroups to a module-level constant (e.g., ALLOWED_USERGROUPS: list[str] = [...]) like other handlers do. This avoids recreating the list per request and makes the authorization policy easier to locate/reuse.

[Copilot]

change = web.ctx.site.get_change(id) can return None (as handled in GET), and not all changesets are undoable (can_undo() may be false, e.g. an already-undone merge or an undo changeset). Calling change._undo() unconditionally can raise an exception or allow unintended repeat/invalid undos. Please add the same not-found handling as GET and gate _undo() behind change.can_undo() (returning an appropriate 4xx / permission-denied response when it’s not undoable).

Suggested change

	change = web.ctx.site.get_change(id)
	change = web.ctx.site.get_change(id)
	if not change:
	web.ctx.status = "404 Not Found"
	return render.notfound(web.ctx.path)
	if not change.can_undo():
	return render_template(
	"permission_denied",
	web.ctx.path,
	"Permission denied to undo this change.",
	)