feat(T02): vehicle management + mobile.de push + vehicle UI

- Vehicle model: 25+ fields, 5 vehicle types, soft-delete
- Vehicle CRUD: 7 API endpoints with JWT auth, filter/sort/paginate
- mobile.de: push/update/delete listings, field mapping, retry logic
- MobileDeListing model for sync status tracking
- Frontend: VehicleList, VehicleForm, VehicleDetail, MobileDeStatus
- 73 backend tests (82% coverage), 16 frontend tests

backend/app/utils/mobilede_mapping.py

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+"""Field mapping utilities for mobile.de listing format conversion."""
+
+from __future__ import annotations
+
+from datetime import date
+from decimal import Decimal
+from typing import Any
+
+from app.models.vehicle import Vehicle
+
+
+# mobile.de category mapping based on vehicle_type
+_CATEGORY_MAP: dict[str, str] = {
+    "lkw": "Truck",
+    "pkw": "Car",
+    "baumaschine": "ConstructionMachine",
+    "stapler": "ForkliftTruck",
+    "transporter": "Van",
+}
+
+# LKW sub-type mapping for mobile.de category refinement
+_LKW_TYPE_MAP: dict[str, str] = {
+    "sattelzugmaschine": "SemiTractor",
+    "sattelauflieger": "SemiTrailer",
+    "kipper": "Tipper",
+    "kuehlmobil": "RefrigeratedVehicle",
+    "tieflader": "LowLoader",
+    "silofahrzeug": "SiloVehicle",
+    "tankwagen": "TankVehicle",
+    "kranwagen": "CraneVehicle",
+    "muldenkipper": "DumperTruck",
+    "sattelkipper": "SemiTipper",
+    "schwertransporter": "HeavyTransporter",
+    "sonderkonstruktion": "SpecialConstruction",
+    "pritsche": "Flatbed",
+    "planenlkw": "TarpaulinTruck",
+    "boxenlkw": "BoxBodyTruck",
+    "iso_lkw": "IsoTruck",
+}
+
+
+def _format_first_registration(reg_date: date | None) -> str | None:
+    """Convert date to YYYY-MM format for mobile.de."""
+    if reg_date is None:
+        return None
+    return reg_date.strftime("%Y-%m")
+
+
+def _format_mileage(vehicle: Vehicle) -> dict[str, Any] | None:
+    """Map mileage or operating hours to mobile.de mileage field."""
+    if vehicle.mileage_km is not None:
+        return {"value": vehicle.mileage_km, "unit": "km"}
+    if vehicle.operating_hours is not None:
+        unit = vehicle.operating_hours_unit or "h"
+        return {"value": float(vehicle.operating_hours), "unit": unit}
+    return None
+
+
+def _format_price(price: Decimal) -> dict[str, Any]:
+    """Map price to mobile.de price format."""
+    return {
+        "amount": float(price),
+        "currency": "EUR",
+    }
+
+
+def _format_power(power_kw: int | None, power_hp: int | None) -> dict[str, Any] | None:
+    """Map power to mobile.de power format."""
+    if power_kw is None and power_hp is None:
+        return None
+    return {
+        "powerKw": power_kw,
+        "powerHp": power_hp,
+    }
+
+
+def _format_category(vehicle: Vehicle) -> str:
+    """Determine mobile.de category from vehicle type and lkw_type."""
+    base = _CATEGORY_MAP.get(vehicle.vehicle_type, "Other")
+    if vehicle.vehicle_type == "lkw" and vehicle.lkw_type:
+        # Try direct match, then strip lkw_ prefix for lookup
+        lkw_key = vehicle.lkw_type
+        if lkw_key in _LKW_TYPE_MAP:
+            return _LKW_TYPE_MAP[lkw_key]
+        stripped = lkw_key.removeprefix("lkw_")
+        if stripped in _LKW_TYPE_MAP:
+            return _LKW_TYPE_MAP[stripped]
+        return base
+    return base
+
+
+def map_fields(vehicle: Vehicle) -> dict[str, Any]:
+    """Map a Vehicle model to the mobile.de listing Ad format.
+
+    Converts internal vehicle fields to the mobile.de REST API listing format.
+    See: https://developer.mobile.de/api/seller-listings
+    """
+    mileage = _format_mileage(vehicle)
+    power = _format_power(vehicle.power_kw, vehicle.power_hp)
+
+    ad: dict[str, Any] = {
+        "vin": vehicle.fin,
+        "make": vehicle.make,
+        "model": vehicle.model,
+        "category": _format_category(vehicle),
+        "price": _format_price(vehicle.price),
+        "availabilityStatus": vehicle.availability,
+        "condition": vehicle.condition,
+    }
+
+    if vehicle.first_registration is not None:
+        ad["firstRegistration"] = _format_first_registration(
+            vehicle.first_registration
+        )
+
+    if mileage is not None:
+        ad["mileage"] = mileage
+
+    if power is not None:
+        ad["power"] = power
+
+    if vehicle.fuel_type is not None:
+        ad["fuelType"] = vehicle.fuel_type
+
+    if vehicle.transmission is not None:
+        ad["transmission"] = vehicle.transmission
+
+    if vehicle.color is not None:
+        ad["color"] = vehicle.color
+
+    if vehicle.year is not None:
+        ad["year"] = vehicle.year
+
+    if vehicle.location is not None:
+        ad["sellerLocation"] = vehicle.location
+
+    if vehicle.machine_type is not None:
+        ad["bodyType"] = vehicle.machine_type
+    elif vehicle.body_type is not None:
+        ad["bodyType"] = vehicle.body_type
+
+    if vehicle.description is not None:
+        ad["description"] = vehicle.description
+
+    return ad