Relabel inbound circle line services: Circle (aim for) and next (fallback)

Consistent with outbound labelling. The first service is the one to aim
for if the Eurostar arrives slightly early; the second is dimmed as it
may not leave enough time for the GWR connection.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_app.py

@@ -629,8 +629,8 @@ def test_results_return_renders_outbound_and_inbound_tables(monkeypatch):
     assert 'return_date=2026-04-17' not in html
     assert 'Circle 09:10 → KX 09:25' in html
     assert 'next 09:15 → KX 09:30' in html
-    assert 'earlier 16:40 → PAD 16:55' in html
-    assert 'Circle 16:45 → PAD 17:00' in html
+    assert 'Circle 16:40 → PAD 16:55' in html
+    assert 'next 16:45 → PAD 17:00' in html
     assert 'title="Tight connection">⚠️</span>' in html
     assert 'ES 9014' in html
     assert 'ES 9035' in html