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

frontend/tests/fixtures/mockData.ts

@@ -30,6 +30,7 @@ export function makeWorkspace(overrides: Partial<Workspace> = {}): Workspace {
     id: 'ws-1',
     name: 'Familjen Testsson',
     createdAt: '2026-01-01T00:00:00',
+    takePlOnRedDays: false,
     ...overrides,
   }
 }