Index page connection time dropdowns now iterate over valid_min_connections
and valid_max_connections passed from the view, so any change to the sets
in app.py is reflected automatically (also adds the missing 45 min option).
Add ⚠️ next to transfer times under 80 minutes in the results table;
store connection_minutes in each trip dict to support the comparison.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
