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/PlanningModelsTests.swift

@@ -341,8 +341,11 @@ struct PlanningModelsTests {
             #expect(!stop.hasGames)
         }
 
-        @Test("equality based on id only")
-        func equality_basedOnId() {
+        @Test("self-equality: same instance is equal to itself")
+        func self_equality() {
+            // ItineraryStop uses auto-generated UUID ids, so two separately constructed
+            // instances will always have different ids. Self-equality is the only
+            // meaningful equality test for this type.
             let stop1 = ItineraryStop(
                 city: "New York",
                 state: "NY",
@@ -354,7 +357,6 @@ struct PlanningModelsTests {
                 firstGameStart: nil
             )
 
-            // Same id via same instance
             #expect(stop1 == stop1)
         }