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/Planning/PlanningPipelineBugRegressionTests.swift

@@ -703,12 +703,23 @@ struct Bug15_DateArithmeticTests {
 
         let planner = ScenarioBPlanner()
         let result = planner.plan(request: request)
-        // Should not crash — verify we get a valid result (success or failure, not a crash)
+        // Bug #15 was a force-unwrap crash in date arithmetic. The fix ensures safe
+        // optional unwrapping. Both outcomes are acceptable here because:
+        // - .success: date arithmetic worked and a route was found
+        // - .failure(.noValidRoutes): date arithmetic worked but driving constraints
+        //   or game spacing prevented a valid route (Boston→NYC in the available window)
+        // The critical assertion is that this code path does NOT crash (no force-unwrap trap).
         switch result {
         case .success(let options):
             #expect(!options.isEmpty, "If success, should have at least one option")
-        case .failure:
-            break // Failure is acceptable — the point is it didn't crash
+        case .failure(let failure):
+            // Any planning-related failure is acceptable — the critical assertion is
+            // that the code path does NOT crash (no force-unwrap trap).
+            let acceptableReasons: [PlanningFailure.FailureReason] = [
+                .noValidRoutes, .noGamesInRange, .constraintsUnsatisfiable, .missingDateRange
+            ]
+            #expect(acceptableReasons.contains { $0 == failure.reason },
+                    "Expected a planning-related failure, got \(failure.reason)")
         }
     }
 }