fix(itinerary): add city to game items for proper constraint validation

Travel constraint validation was not working because ItineraryConstraints
had no game items to validate against - games came from RichGame objects
but were never converted to ItineraryItem for constraint checking.

Changes:
- Add city parameter to ItemKind.game enum case
- Create game ItineraryItems from RichGame data in buildItineraryData()
- Update isValidTravelPosition to compare against actual game sortOrders
- Fix tests to use appropriate game sortOrder conventions

Now travel is properly constrained to appear before arrival city games
and after departure city games.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

SportsTimeTests/Features/Trip/ItineraryTestHelpers.swift

@@ -108,7 +108,7 @@ enum ItineraryTestHelpers {
             tripId: testTripId,
             day: day,
             sortOrder: sortOrder,
-            kind: .game(gameId: "game-\(city)-\(UUID().uuidString.prefix(4))")
+            kind: .game(gameId: "game-\(city)-\(UUID().uuidString.prefix(4))", city: city)
         )
     }