feat: Live-Stempel-Uhr, Break-UI, Balance-Widget, Approval-Queue + PDF-Export (WeasyPrint)

Frontend (TimeTrackingPage):
- Live-Arbeitsuhr (HH:MM:SS) während eingestempelt
- Break-Start/End-Buttons mit laufender Pausenuhr
- Wochen-Balance-Widget (gearbeitet / erwartet / überstunden)
- Approval-Queue Tab für Manager/HR/Admin (pending entries genehmigen/ablehnen)

Backend (Reports):
- weasyprint>=61.0 in requirements.txt
- 3 neue PDF-Export-Tests (Zeit, Abwesenheit, Überstunden)

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

backend/app/routers/absence.py

@@ -0,0 +1,159 @@
+import uuid
+from datetime import date, datetime
+
+from pydantic import BaseModel, Field
+
+from app.models.absence import AbsenceStatus
+
+
+# ── AbsenceType ───────────────────────────────────────────────────────────────
+
+class AbsenceTypeOut(BaseModel):
+    model_config = {"from_attributes": True}
+
+    id: uuid.UUID
+    company_id: uuid.UUID
+    name: str
+    color: str
+    requires_approval: bool
+    deducts_vacation: bool
+    is_paid: bool
+    max_days_per_year: int | None
+    is_active: bool
+
+
+class AbsenceTypeCreate(BaseModel):
+    name: str = Field(min_length=1, max_length=255)
+    color: str = Field("#3B82F6", pattern=r"^#[0-9A-Fa-f]{6}$")
+    requires_approval: bool = True
+    deducts_vacation: bool = False
+    is_paid: bool = True
+    max_days_per_year: int | None = Field(None, ge=1)
+
+
+class AbsenceTypeUpdate(BaseModel):
+    name: str | None = Field(None, min_length=1, max_length=255)
+    color: str | None = Field(None, pattern=r"^#[0-9A-Fa-f]{6}$")
+    requires_approval: bool | None = None
+    deducts_vacation: bool | None = None
+    is_paid: bool | None = None
+    max_days_per_year: int | None = Field(None, ge=1)
+    is_active: bool | None = None
+
+
+# ── Absence ───────────────────────────────────────────────────────────────────
+
+class AbsenceOut(BaseModel):
+    model_config = {"from_attributes": True}
+
+    id: uuid.UUID
+    user_id: uuid.UUID
+    type_id: uuid.UUID
+    start_date: date
+    end_date: date
+    half_day_start: bool
+    half_day_end: bool
+    working_days: float
+    status: AbsenceStatus
+    approved_by: uuid.UUID | None
+    substitute_id: uuid.UUID | None
+    note: str | None
+    correction_note: str | None
+    rejection_reason: str | None
+    created_at: datetime
+
+
+class AbsenceCreate(BaseModel):
+    type_id: uuid.UUID
+    start_date: date
+    end_date: date
+    half_day_start: bool = False
+    half_day_end: bool = False
+    substitute_id: uuid.UUID | None = None
+    note: str | None = None
+    for_user_id: uuid.UUID | None = None  # HR/Admin: Abwesenheit für anderen Mitarbeiter anlegen
+
+    def model_post_init(self, __context) -> None:
+        if self.end_date < self.start_date:
+            raise ValueError("end_date must be >= start_date")
+
+
+class AbsenceUpdate(BaseModel):
+    type_id: uuid.UUID | None = None
+    start_date: date | None = None
+    end_date: date | None = None
+    half_day_start: bool | None = None
+    half_day_end: bool | None = None
+    substitute_id: uuid.UUID | None = None
+    note: str | None = None
+    correction_note: str | None = None  # Pflicht bei Änderung genehmigter Anträge (Mitarbeiter)
+
+    def model_post_init(self, __context) -> None:
+        if self.start_date and self.end_date and self.end_date < self.start_date:
+            raise ValueError("end_date must be >= start_date")
+
+
+class AbsenceReject(BaseModel):
+    rejection_reason: str = Field(min_length=1)
+
+
+class AbsenceListResponse(BaseModel):
+    total: int
+    items: list[AbsenceOut]
+
+
+# ── VacationBalance ───────────────────────────────────────────────────────────
+
+class VacationBalanceOut(BaseModel):
+    model_config = {"from_attributes": True}
+
+    id: uuid.UUID
+    user_id: uuid.UUID
+    year: int
+    entitled_days: int
+    carried_over: int
+    used_days: int
+    remaining_days: int
+    pending_days: float = 0  # Ausstehende Anträge (noch nicht genehmigt)
+
+
+# ── PublicHoliday ─────────────────────────────────────────────────────────────
+
+class PublicHolidayOut(BaseModel):
+    model_config = {"from_attributes": True}
+
+    id: uuid.UUID
+    country: str
+    state: str | None
+    date: date
+    name: str
+    year: int
+
+
+class PublicHolidayCreate(BaseModel):
+    country: str = Field("DE", min_length=2, max_length=10)
+    state: str | None = Field(None, max_length=10)
+    date: date
+    name: str = Field(min_length=1, max_length=255)
+
+
+# ── OvertimeBalance ───────────────────────────────────────────────────────────
+
+class OvertimeBalanceOut(BaseModel):
+    total_hours: float
+    taken_hours: float
+    available_hours: float
+
+
+# ── Calendar ──────────────────────────────────────────────────────────────────
+
+class CalendarEntry(BaseModel):
+    user_id: uuid.UUID
+    user_name: str
+    absence_id: uuid.UUID
+    type_name: str
+    type_color: str
+    start_date: date
+    end_date: date
+    status: AbsenceStatus
+    working_days: float