Let a household choose to be paid for the red days

Asking for a full week off never spent anything on the Saturday, the
Sunday or a holiday, and a test now says so outright rather than leaving
it to be rediscovered. Those days are free because vacation cannot be
taken on a day that is not a working day.

Parental benefit is a payment rather than a schedule, though, so it can
be drawn on a red day to turn an unpaid day off into a paid one — at the
cost of a day the family would otherwise keep. That is now a workspace
setting, off by default, and it never reaches for a vacation day. With it
off the planner behaves exactly as before.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ei7gCZzdd751uZtPzb1Pep

backend/app/routers/workspace.py

@@ -84,7 +84,9 @@ async def update_workspace(
     service: WorkspaceServiceDep,
 ) -> WorkspaceResponse:
     try:
-        ws = await service.update_workspace(workspace_id, payload.name)
+        ws = await service.update_workspace(
+            workspace_id, payload.name, take_pl_on_red_days=payload.take_pl_on_red_days
+        )
     except (NotFoundError, ValidationError) as exc:
         code = (
             status.HTTP_404_NOT_FOUND