Audit and fix 52 test correctness issues across 22 files

Systematic audit of 1,191 tests found tests written to pass rather than
verify correctness. Key fixes:

Infrastructure:
- TestClock: fixed timezone from .current to America/New_York (deterministic)
- TestFixtures: added 1.3x road routing factor to match production
- ItineraryTestHelpers: real per-city coordinates instead of hardcoded (40,-80)

Planning tests:
- Added missing Scenario E factory dispatch tests
- Tightened 12 loose assertions (>= 1 → == 8.0, > 0 → range checks)
- Fixed 4 no-op tests that accepted both success and failure
- Fixed wrong repeat-city invariant (was checking same-day, not different-day)
- Fixed tautological assertion in missing-stadium edge case

Services/Domain/Export tests:
- Replaced 4 placeholder tests (#expect(true)) with real assertions
- Fixed tautological assertions in POISearchServiceTests
- Fixed Chicago coordinate in RegionMapSelectorTests (-89 → -87.6553)
- Added sort order verification to ItineraryRowFlatteningTests

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

SportsTimeTests/Services/ScoreResolutionCacheTests.swift

@@ -118,11 +118,15 @@ struct CacheStatsTests {
     }
 
     /// - Invariant: sum of entriesBySport <= totalEntries
+    // NOTE: CacheStats is a plain data struct — this test documents the expected
+    // relationship between sport entries and total, not enforcement by the cache.
+    // The struct does not validate or clamp values; callers are responsible for
+    // providing consistent data.
     @Test("Invariant: sport entries sum does not exceed total")
     func invariant_sportEntriesSumDoesNotExceedTotal() {
         let bySport: [Sport: Int] = [.mlb: 30, .nba: 40, .nhl: 30]
         let stats = makeStats(totalEntries: 100, entriesBySport: bySport)
-        let sportSum = bySport.values.reduce(0, +)
+        let sportSum = stats.entriesBySport.values.reduce(0, +)
         #expect(sportSum <= stats.totalEntries)
     }
 }