feat(T04): Rentman integration – equipment sync, API endpoints, frontend updates

- Update equipment model with Rentman-compatible fields
- Add/Update equipment router endpoints for sync operations
- Enhance rentman_service with full API client logic
- Improve sync_service for bidirectional equipment sync
- Update docker-compose with Rentman env vars
- Update frontend useApi composable and nuxt config
- Update mietkatalog pages with Rentman-integrated data display
- Add images/ to .gitignore (binary assets, 36MB)

backend/app/routers/equipment.py

@@ -1,5 +1,7 @@
-"""Equipment API router: list, detail, categories."""
+"""Equipment API router: list, detail, categories, image."""
+import os
 from fastapi import APIRouter, Depends, HTTPException, Query, status
+from fastapi.responses import FileResponse
 from sqlalchemy import select, func, or_
 from sqlalchemy.ext.asyncio import AsyncSession
 from typing import Any
@@ -10,6 +12,8 @@ from app.cache import cache
 
 router = APIRouter(prefix="/api/equipment", tags=["equipment"])
 
+IMAGES_DIR = "/data/images/equipment"
+
 
 @router.get("", response_model=PaginatedResponse)
 async def list_equipment(
@@ -73,6 +77,15 @@ async def list_categories(db: AsyncSession = Depends(get_db)) -> Any:
     return categories
 
 
+@router.get("/{equipment_id}/image")
+async def get_equipment_image(equipment_id: int, db: AsyncSession = Depends(get_db)) -> Any:
+    """Serve the locally stored image for an equipment item."""
+    image_path = os.path.join(IMAGES_DIR, f"{equipment_id}.jpg")
+    if os.path.exists(image_path):
+        return FileResponse(image_path, media_type="image/jpeg")
+    raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Image not found")
+
+
 @router.get("/{equipment_id}", response_model=EquipmentDetail)
 async def get_equipment(equipment_id: int, db: AsyncSession = Depends(get_db)) -> Any:
     """Return a single equipment detail by ID."""
@@ -86,5 +99,5 @@ async def get_equipment(equipment_id: int, db: AsyncSession = Depends(get_db)) -
     if not item:
         raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Equipment not found")
     response = EquipmentDetail.model_validate(item).model_dump()
-    await cache.set(cache_key, response.model_dump(), ttl=3600)
+    await cache.set(cache_key, response, ttl=3600)
     return response