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/Export/POISearchServiceTests.swift

@@ -64,23 +64,23 @@ struct POITests {
         #expect(justOverPOI.formattedDistance.contains("mi"))
     }
 
-    /// - Expected Behavior: Zero distance formats correctly
+    /// - Expected Behavior: Zero distance formats as "0 ft"
     @Test("formattedDistance: handles zero distance")
     func formattedDistance_zero() {
+        // 0 meters = 0 feet, and 0 miles < 0.1 so it uses feet format
+        // String(format: "%.0f ft", 0 * 3.28084) == "0 ft"
         let poi = makePOI(distanceMeters: 0)
         let formatted = poi.formattedDistance
-        #expect(formatted.contains("0") || formatted.contains("ft"))
+        #expect(formatted == "0 ft", "Zero distance should format as '0 ft', got '\(formatted)'")
     }
 
-    /// - Expected Behavior: Large distance formats correctly
+    /// - Expected Behavior: Large distance formats correctly as miles
     @Test("formattedDistance: handles large distance")
     func formattedDistance_large() {
-        // 5000 meters = ~3.1 miles
+        // 5000 meters * 0.000621371 = 3.106855 miles → "3.1 mi"
         let poi = makePOI(distanceMeters: 5000)
         let formatted = poi.formattedDistance
-
-        #expect(formatted.contains("mi"))
-        #expect(formatted.contains("3.1") || formatted.contains("3.") || Double(formatted.replacingOccurrences(of: " mi", with: ""))! > 3.0)
+        #expect(formatted == "3.1 mi", "5000m should format as '3.1 mi', got '\(formatted)'")
     }
 
     // MARK: - Invariant Tests