refactor(tests): TDD rewrite of all unit tests with spec documentation

Complete rewrite of unit test suite using TDD methodology:

Planning Engine Tests:
- GameDAGRouterTests: Beam search, anchor games, transitions
- ItineraryBuilderTests: Stop connection, validators, EV enrichment
- RouteFiltersTests: Region, time window, scoring filters
- ScenarioA/B/C/D PlannerTests: All planning scenarios
- TravelEstimatorTests: Distance, duration, travel days
- TripPlanningEngineTests: Orchestration, caching, preferences

Domain Model Tests:
- AchievementDefinitionsTests, AnySportTests, DivisionTests
- GameTests, ProgressTests, RegionTests, StadiumTests
- TeamTests, TravelSegmentTests, TripTests, TripPollTests
- TripPreferencesTests, TripStopTests, SportTests

Service Tests:
- FreeScoreAPITests, RouteDescriptionGeneratorTests
- SuggestedTripsGeneratorTests

Export Tests:
- ShareableContentTests (card types, themes, dimensions)

Bug fixes discovered through TDD:
- ShareCardDimensions: mapSnapshotSize exceeded available width (960x480)
- ScenarioBPlanner: Added anchor game validation filter

All tests include:
- Specification tests (expected behavior)
- Invariant tests (properties that must always hold)
- Edge case tests (boundary conditions)

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

SportsTime/Export/Sharing/ShareableContent.swift

@@ -149,8 +149,8 @@ enum ShareError: Error, LocalizedError {
 
 enum ShareCardDimensions {
     static let cardSize = CGSize(width: 1080, height: 1920)
-    static let mapSnapshotSize = CGSize(width: 1000, height: 500)
-    static let routeMapSize = CGSize(width: 1000, height: 600)
+    static let mapSnapshotSize = CGSize(width: 960, height: 480)  // Must fit within cardSize.width - 2*padding
+    static let routeMapSize = CGSize(width: 960, height: 576)     // Must fit within cardSize.width - 2*padding
     static let padding: CGFloat = 60
     static let headerHeight: CGFloat = 120
     static let footerHeight: CGFloat = 100