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/Features/Trip/ItineraryTestHelpers.swift

@@ -5,6 +5,7 @@
 //  Shared test fixtures and helpers for Itinerary tests.
 //
 
+import CoreLocation
 import Foundation
 @testable import SportsTime
 
@@ -71,13 +72,14 @@ enum ItineraryTestHelpers {
             isPlayoff: false
         )
 
+        let coord = TestFixtures.coordinates[city] ?? CLLocationCoordinate2D(latitude: 40.0, longitude: -80.0)
         let stadium = Stadium(
             id: "stadium-\(city)",
             name: "\(city) Stadium",
             city: city,
             state: "XX",
-            latitude: 40.0,
-            longitude: -80.0,
+            latitude: coord.latitude,
+            longitude: coord.longitude,
             capacity: 40000,
             sport: .mlb
         )