feat: Stunden-Auszahlung Feature (/hr/payouts)

- Backend: Model HoursPayout, Schema, Router GET/POST/DELETE
- GET /hr/payouts: HR/Admin sehen alle, Employee/Manager nur eigene
- POST /hr/payouts: reduziert OvertimeBalance.taken_hours sofort
- DELETE /hr/payouts/{id}: storniert und bucht Stunden zurück
- AuditLog-Einträge bei Anlegen und Stornieren
- Migration 0030: hours_payouts Tabelle
- Frontend: /hr/payouts Seite (lila, 💸) mit Filter, Tabelle, Modal
- Modal zeigt verfügbares Überstundenguthaben + Warnung bei Überziehung
- Navigation: Stunden-Auszahlung (HR/COMPANY_ADMIN/SUPER_ADMIN)

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

backend/app/schemas/hours_payout.py

@@ -0,0 +1,33 @@
+import uuid
+from datetime import datetime
+from decimal import Decimal
+from pydantic import BaseModel, Field
+
+
+class HoursPayoutCreate(BaseModel):
+    user_id: uuid.UUID
+    hours: Decimal = Field(gt=0, le=999.99, decimal_places=2)
+    period_year: int | None = Field(None, ge=2000, le=2100)
+    period_month: int | None = Field(None, ge=1, le=12)
+    note: str | None = Field(None, max_length=500)
+
+
+class HoursPayoutOut(BaseModel):
+    model_config = {"from_attributes": True}
+
+    id: uuid.UUID
+    company_id: uuid.UUID
+    user_id: uuid.UUID
+    user_name: str          # Computed: first_name + last_name (wird im Router gesetzt)
+    hours: Decimal
+    period_year: int | None
+    period_month: int | None
+    note: str | None
+    created_by: uuid.UUID
+    created_by_name: str    # Computed im Router
+    created_at: datetime
+
+
+class HoursPayoutListResponse(BaseModel):
+    payouts: list[HoursPayoutOut]
+    total_count: int