feat: agent-11 PR3 – Scheduler + Erinnerungs-Mails + Notification-Prefs

Geplante Erinnerungen (Feature-Parität mit Urlaubsverwaltung):

- APScheduler (AsyncIOScheduler) in der FastAPI-Lifespan; tägliche Jobs ab
  settings.reminder_hour. Redis-Tageslock gegen Doppelversand bei mehreren
  Prozessen; jeder Job mit eigener Session + RLS-Bypass.
- Drei Jobs (auch einzeln aufrufbar): offene Anträge an Genehmiger,
  Resturlaub-Verfall-Vorwarnung an Mitarbeiter, fehlende AU an HR.
- Pro-User notification_prefs (JSONB, opt-out); GET/PATCH /users/me/notification-prefs
  + ProfilePage-UI; Vertreter-Mail respektiert die Prefs.
- Manueller Trigger POST /companies/me/run-reminders (Admin) – gleiche Logik,
  firmen-scoped (testbar ohne Warten).
- Bugfix: GET-/PATCH-Urlaubskonto (update_balance) nutzte nicht existente
  Felder (base_days/carried_over_days/ip_address) → korrigiert auf
  entitled_days/carried_over/ip + company_id; available_days ergänzt.

Migration 0037 (users.notification_prefs). 188/188 Tests grün. Deployed 137 + 164.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/app/routers/absences.py

@@ -426,28 +426,31 @@ async def update_balance(
     balance = await absence_service.get_balance(user_id, year, db)
 
     # Alte Werte für AuditLog sichern
-    old_base = balance.base_days
-    old_special = balance.special_days
-    old_carried = balance.carried_over_days
+    old_value = {
+        "entitled_days": balance.entitled_days,
+        "special_days": balance.special_days,
+        "carried_over": balance.carried_over,
+    }
 
     for field, value in data.model_dump(exclude_unset=True).items():
         setattr(balance, field, value)
 
     # AuditLog schreiben
     db.add(AuditLog(
+        company_id=current_user.company_id,
         user_id=current_user.id,
         action="update_vacation_balance",
         entity_type="vacation_balance",
         entity_id=balance.id,
-        old_value={"base_days": old_base, "special_days": old_special, "carried_over_days": old_carried},
+        old_value=old_value,
         new_value={
-            "base_days": balance.base_days,
+            "entitled_days": balance.entitled_days,
             "special_days": balance.special_days,
-            "carried_over_days": balance.carried_over_days,
+            "carried_over": balance.carried_over,
             "target_user_id": str(user_id),
             "year": year,
         },
-        ip_address=get_client_ip(request),
+        ip=get_client_ip(request),
     ))
 
     await db.commit()
@@ -456,6 +459,7 @@ async def update_balance(
     expires_at, expired = _carryover_expiry(company, year) if company else (None, False)
     return VacationBalanceOut.model_validate(balance).model_copy(update={
         "pending_days": pending,
+        "available_days": absence_service.effective_available(balance, expired),
         "carried_over_expires_at": expires_at,
         "carried_over_expired": expired,
     })