Add return and inbound journey support

tests/test_trip_planner.py

@@ -1,5 +1,10 @@
 import pytest
-from trip_planner import combine_trips, find_unreachable_morning_eurostars, _fmt_duration
+from trip_planner import (
+    combine_inbound_trips,
+    combine_trips,
+    find_unreachable_morning_eurostars,
+    _fmt_duration,
+)
 
 DATE = '2026-03-30'
 
@@ -178,3 +183,28 @@ def test_find_unreachable_eurostars_returns_empty_when_all_connectable():
     ]
 
     assert find_unreachable_morning_eurostars(gwr, eurostar, DATE) == []
+
+
+def test_combine_inbound_trips_pairs_eurostar_to_paddington_departure():
+    eurostar = [{
+        'depart_destination': '15:12',
+        'arrive_st_pancras': '16:30',
+        'destination': 'Paris Gare du Nord',
+        'train_number': 'ES 9035',
+    }]
+    gwr = [{
+        'depart_paddington': '17:15',
+        'arrive_destination': '18:55',
+        'headcode': '1B99',
+    }]
+    fares = {'17:15': {'ticket': 'Off-Peak Single', 'price': 63.60, 'code': 'SVS'}}
+
+    trips = combine_inbound_trips(eurostar, gwr, DATE, min_connection_minutes=30, max_connection_minutes=120, gwr_fares=fares)
+
+    assert len(trips) == 1
+    assert trips[0]['depart_destination'] == '15:12'
+    assert trips[0]['arrive_st_pancras'] == '16:30'
+    assert trips[0]['depart_paddington'] == '17:15'
+    assert trips[0]['arrive_uk_station'] == '18:55'
+    assert trips[0]['ticket_price'] == 63.60
+    assert trips[0]['check_in_by'] == '14:42'