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>

SportsTimeTests/Services/VisitPhotoServiceTests.swift

@@ -0,0 +1,108 @@
+//
+//  VisitPhotoServiceTests.swift
+//  SportsTimeTests
+//
+//  TDD specification tests for VisitPhotoService types.
+//
+
+import Testing
+import Foundation
+@testable import SportsTime
+
+// MARK: - PhotoServiceError Tests
+
+@Suite("PhotoServiceError")
+struct PhotoServiceErrorTests {
+
+    // MARK: - Specification Tests: errorDescription
+
+    /// - Expected Behavior: notSignedIn explains iCloud requirement
+    @Test("errorDescription: notSignedIn mentions iCloud")
+    func errorDescription_notSignedIn() {
+        let error = PhotoServiceError.notSignedIn
+        #expect(error.errorDescription != nil)
+        #expect(error.errorDescription!.lowercased().contains("icloud") || error.errorDescription!.lowercased().contains("sign in"))
+    }
+
+    /// - Expected Behavior: uploadFailed includes the message
+    @Test("errorDescription: uploadFailed includes message")
+    func errorDescription_uploadFailed() {
+        let error = PhotoServiceError.uploadFailed("Network timeout")
+        #expect(error.errorDescription != nil)
+        #expect(error.errorDescription!.contains("Network timeout") || error.errorDescription!.lowercased().contains("upload"))
+    }
+
+    /// - Expected Behavior: downloadFailed includes the message
+    @Test("errorDescription: downloadFailed includes message")
+    func errorDescription_downloadFailed() {
+        let error = PhotoServiceError.downloadFailed("Connection lost")
+        #expect(error.errorDescription != nil)
+        #expect(error.errorDescription!.contains("Connection lost") || error.errorDescription!.lowercased().contains("download"))
+    }
+
+    /// - Expected Behavior: thumbnailGenerationFailed explains the issue
+    @Test("errorDescription: thumbnailGenerationFailed mentions thumbnail")
+    func errorDescription_thumbnailGenerationFailed() {
+        let error = PhotoServiceError.thumbnailGenerationFailed
+        #expect(error.errorDescription != nil)
+        #expect(error.errorDescription!.lowercased().contains("thumbnail"))
+    }
+
+    /// - Expected Behavior: invalidImage explains invalid data
+    @Test("errorDescription: invalidImage mentions invalid")
+    func errorDescription_invalidImage() {
+        let error = PhotoServiceError.invalidImage
+        #expect(error.errorDescription != nil)
+        #expect(error.errorDescription!.lowercased().contains("invalid"))
+    }
+
+    /// - Expected Behavior: assetNotFound explains missing photo
+    @Test("errorDescription: assetNotFound mentions not found")
+    func errorDescription_assetNotFound() {
+        let error = PhotoServiceError.assetNotFound
+        #expect(error.errorDescription != nil)
+        #expect(error.errorDescription!.lowercased().contains("not found") || error.errorDescription!.lowercased().contains("photo"))
+    }
+
+    /// - Expected Behavior: quotaExceeded explains storage limit
+    @Test("errorDescription: quotaExceeded mentions quota")
+    func errorDescription_quotaExceeded() {
+        let error = PhotoServiceError.quotaExceeded
+        #expect(error.errorDescription != nil)
+        #expect(error.errorDescription!.lowercased().contains("quota") || error.errorDescription!.lowercased().contains("storage"))
+    }
+
+    // MARK: - Invariant Tests
+
+    /// - Invariant: All errors have non-empty descriptions
+    @Test("Invariant: all errors have descriptions")
+    func invariant_allHaveDescriptions() {
+        let errors: [PhotoServiceError] = [
+            .notSignedIn,
+            .uploadFailed("test"),
+            .downloadFailed("test"),
+            .thumbnailGenerationFailed,
+            .invalidImage,
+            .assetNotFound,
+            .quotaExceeded
+        ]
+
+        for error in errors {
+            #expect(error.errorDescription != nil)
+            #expect(!error.errorDescription!.isEmpty)
+        }
+    }
+
+    /// - Invariant: uploadFailed and downloadFailed preserve their messages
+    @Test("Invariant: parameterized errors preserve message")
+    func invariant_parameterizedErrorsPreserveMessage() {
+        let testMessage = "Test error message 12345"
+
+        let uploadError = PhotoServiceError.uploadFailed(testMessage)
+        let downloadError = PhotoServiceError.downloadFailed(testMessage)
+
+        // The message should appear somewhere in the description
+        #expect(uploadError.errorDescription!.contains(testMessage))
+        #expect(downloadError.errorDescription!.contains(testMessage))
+    }
+}