feat: refine itinerary flow and add OSRM connector metrics

backend/server/.env.example

@@ -26,6 +26,7 @@ EMAIL_BACKEND='console'
 # DEFAULT_FROM_EMAIL='user@example.com'
 
 # GOOGLE_MAPS_API_KEY='key'
+# OSRM_BASE_URL='https://router.project-osrm.org'  # replace with self-host URL if needed (e.g. http://osrm:5000)
 
 # ACCOUNT_EMAIL_VERIFICATION='none'  # 'none', 'optional', 'mandatory' # You can change this as needed for your environment
 
@@ -48,4 +49,4 @@ EMAIL_BACKEND='console'
 # Pull and merge weblate changes
 # git fetch weblate
 # git merge --squash weblate/development
-# ------------------- #
+# ------------------- #