feat: Überstunden-Kappung + Jahresverfall pro Firma konfigurierbar

Backend:
- Company: overtime_cap_hours, overtime_expiry_enabled/month/day,
  overtime_max_carryover_hours
- OvertimeBalance: last_expiry_applied_at
- Migration 0031: neue Spalten in companies + overtime_balances
- _recalculate_overtime_balance: Kappung direkt nach Berechnung
- apply_overtime_expiry_if_needed(): lazy Verfall beim Balance-Abruf
- GET /absences/overtime-balance: prüft + wendet Verfall automatisch an
- POST /absences/overtime-balance/apply-expiry: manueller Trigger (Admin)

Frontend:
- CompanySettingsPage: neuer Block 'Überstunden-Konto'
  - Toggle Kappungsgrenze + Stunden-Input
  - Toggle Jahresverfall + Stichtag (Tag/Monat) + max. Übertrag
  - 'Verfall anwenden'-Button für Admins

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/models/company.py

@@ -55,6 +55,13 @@ class Company(Base):
     # Freizeitausgleich-Konfiguration
     overtime_overdraft_allowed: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True)
     overtime_warning_threshold_hours: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    # Überstunden-Kappung
+    overtime_cap_hours: Mapped[int | None] = mapped_column(Integer, nullable=True)
+    # Überstunden-Verfall
+    overtime_expiry_enabled: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
+    overtime_expiry_month: Mapped[int] = mapped_column(Integer, nullable=False, default=3)   # März
+    overtime_expiry_day: Mapped[int] = mapped_column(Integer, nullable=False, default=31)    # 31.
+    overtime_max_carryover_hours: Mapped[int | None] = mapped_column(Integer, nullable=True) # None = alles
 
     # Relationships
     users: Mapped[list["User"]] = relationship("User", back_populates="company", lazy="noload")

backend/app/models/overtime_balance.py

@@ -34,6 +34,7 @@ class OvertimeBalance(Base):
     total_hours: Mapped[Decimal] = mapped_column(Numeric(8, 2), default=Decimal("0"))
     taken_hours: Mapped[Decimal] = mapped_column(Numeric(8, 2), default=Decimal("0"))
     last_calculated: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+    last_expiry_applied_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
     updated_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), server_default=func.now(), onupdate=func.now()

backend/app/routers/absences.py

@@ -210,6 +210,15 @@ async def get_overtime_balance(
     )
     if bal is None:
         return OvertimeBalanceOut(total_hours=0, taken_hours=0, available_hours=0)
+
+    # Verfall anwenden wenn nötig
+    from app.services.report_service import apply_overtime_expiry_if_needed
+    from app.models.company import Company as CompanyModel
+    company = await db.get(CompanyModel, current_user.company_id)
+    changed = await apply_overtime_expiry_if_needed(bal, company, db)
+    if changed:
+        await db.commit()
+
     return OvertimeBalanceOut(
         total_hours=float(bal.total_hours),
         taken_hours=float(bal.taken_hours),
@@ -217,6 +226,29 @@ async def get_overtime_balance(
     )
 
 
+@router.post("/absences/overtime-balance/apply-expiry")
+async def apply_overtime_expiry_all(
+    current_user: User = require_role(UserRole.COMPANY_ADMIN, UserRole.SUPER_ADMIN),
+    db: AsyncSession = Depends(get_db),
+):
+    """Überstunden-Verfall manuell für alle Mitarbeiter der Firma anwenden."""
+    from sqlalchemy import select as sa_select
+    from app.models.company import Company as CompanyModel
+    from app.services.report_service import apply_overtime_expiry_if_needed
+
+    company = await db.get(CompanyModel, current_user.company_id)
+    balances = list(await db.scalars(
+        sa_select(OvertimeBalance).where(OvertimeBalance.company_id == current_user.company_id)
+    ))
+    applied_count = 0
+    for bal in balances:
+        changed = await apply_overtime_expiry_if_needed(bal, company, db)
+        if changed:
+            applied_count += 1
+    await db.commit()
+    return {"applied_to": applied_count, "total": len(balances)}
+
+
 @router.get("/absences/", response_model=AbsenceListResponse)
 async def list_absences(
     current_user: CurrentUser,

backend/app/schemas/company.py

@@ -24,6 +24,11 @@ class CompanyOut(BaseModel):
     mobile_stamping_enabled: bool = True
     overtime_overdraft_allowed: bool = True
     overtime_warning_threshold_hours: int = 0
+    overtime_cap_hours: int | None = None
+    overtime_expiry_enabled: bool = False
+    overtime_expiry_month: int = 3
+    overtime_expiry_day: int = 31
+    overtime_max_carryover_hours: int | None = None
     kiosk_require_approval: bool = True
     kiosk_track_current_user: bool = True
     kiosk_heartbeat_interval_sec: int = 30
@@ -39,6 +44,11 @@ class CompanyUpdate(BaseModel):
     mobile_stamping_enabled: bool | None = None
     overtime_overdraft_allowed: bool | None = None
     overtime_warning_threshold_hours: int | None = Field(None, ge=0)
+    overtime_cap_hours: int | None = Field(None, ge=1, le=9999)
+    overtime_expiry_enabled: bool | None = None
+    overtime_expiry_month: int | None = Field(None, ge=1, le=12)
+    overtime_expiry_day: int | None = Field(None, ge=1, le=31)
+    overtime_max_carryover_hours: int | None = Field(None, ge=0, le=9999)
     kiosk_require_approval: bool | None = None
     kiosk_track_current_user: bool | None = None
     kiosk_heartbeat_interval_sec: int | None = Field(None, ge=10, le=120)

backend/app/services/report_service.py

@@ -242,9 +242,63 @@ async def _recalculate_overtime_balance(
 
     bal.total_hours = Decimal(str(round(overtime, 2)))
     bal.last_calculated = datetime.utcnow()
+
+    # Kappung anwenden
+    company = await db.get(Company, user.company_id)
+    if company and company.overtime_cap_hours is not None:
+        cap = Decimal(str(company.overtime_cap_hours))
+        if bal.total_hours > cap:
+            bal.total_hours = cap
+
     return bal
 
 
+async def apply_overtime_expiry_if_needed(
+    bal: OvertimeBalance,
+    company,  # Company model
+    db: AsyncSession,
+) -> bool:
+    """
+    Prüft ob der Überstunden-Verfall angewendet werden muss und tut es ggf.
+    Gibt True zurück wenn Verfall angewendet wurde.
+    """
+    if not company or not company.overtime_expiry_enabled:
+        return False
+
+    today = date.today()
+    try:
+        expiry_this_year = date(today.year, company.overtime_expiry_month, company.overtime_expiry_day)
+    except ValueError:
+        # Ungültiges Datum (z.B. 31. Februar) – überspringen
+        return False
+
+    expiry_last_year_year = today.year - 1
+    try:
+        expiry_last_year = date(expiry_last_year_year, company.overtime_expiry_month, company.overtime_expiry_day)
+    except ValueError:
+        expiry_last_year = None
+
+    last_applicable_expiry = expiry_this_year if today >= expiry_this_year else expiry_last_year
+    if last_applicable_expiry is None:
+        return False
+
+    # Schon angewendet?
+    if bal.last_expiry_applied_at:
+        applied_date = bal.last_expiry_applied_at.date() if hasattr(bal.last_expiry_applied_at, 'date') else bal.last_expiry_applied_at
+        if applied_date >= last_applicable_expiry:
+            return False
+
+    # Verfall anwenden: available_hours auf max_carryover kappen
+    available = bal.total_hours - bal.taken_hours
+    if company.overtime_max_carryover_hours is not None:
+        max_carry = Decimal(str(company.overtime_max_carryover_hours))
+        if available > max_carry:
+            bal.total_hours = bal.taken_hours + max_carry
+
+    bal.last_expiry_applied_at = datetime.utcnow()
+    return True
+
+
 def _check_arbzg_day(entry: TimeEntry) -> list[str]:
     """ArbZG-Prüfung für einen einzelnen Zeiteintrag."""
     if entry.end_time is None: