Fix: Tagesbild stabil (date-seeded statt random), preview_url für schnelleres Laden — SW by-v483, APP_VER 460

backend/routes/dogs.py

@@ -118,7 +118,9 @@ async def get_welcome_dashboard(dog_id: int, user=Depends(get_current_user)):
         ).fetchall()
         random_photo = None
         if photos:
-            chosen_url = _random.choice(photos)["url"]
+            import datetime as _dt2
+            day_num    = (_dt2.date.today() - _dt2.date(2024, 1, 1)).days
+            chosen_url = photos[day_num % len(photos)]["url"]
             random_photo = {
                 "url":         chosen_url,
                 "preview_url": preview_url_from(chosen_url),