fix(config): delegate all API routes through include('api.urls')

config/urls.py was manually importing TripPlanView and hardcoding
one path — api/urls.py was completely ignored by Django.
geocode/reverse/ returned 404 in production despite being correctly
registered in api/urls.py.
Fix: replace manual route with include() pattern so all current
and future api/ routes work automatically.

Author: FelixBC

backend/config/urls.py

@@ -1,6 +1,5 @@
-from django.urls import path
-from api.views import TripPlanView
+from django.urls import path, include
 
 urlpatterns = [
-    path("api/trip/plan/", TripPlanView.as_view()),
+    path("api/", include("api.urls")),
 ]