test(planning): complete test suite with Phase 11 edge cases

Implement comprehensive test infrastructure and all 124 tests across 11 phases:

- Phase 0: Test infrastructure (fixtures, mocks, helpers)
- Phases 1-10: Core planning engine tests (previously implemented)
- Phase 11: Edge case omnibus (11 new tests)
  - Data edge cases: nil stadiums, malformed dates, invalid coordinates
  - Boundary conditions: driving limits, radius boundaries
  - Time zone cases: cross-timezone games, DST transitions

Reorganize test structure under Planning/ directory with proper organization.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

SportsTimeTests/Helpers/TestConstants.swift

@@ -0,0 +1,87 @@
+//
+//  TestConstants.swift
+//  SportsTimeTests
+//
+//  Constants used across test suites for consistent test configuration.
+//
+
+import Foundation
+
+enum TestConstants {
+    // MARK: - Distance & Radius
+
+    /// Standard radius for "nearby" game filtering (miles)
+    static let nearbyRadiusMiles: Double = 50.0
+
+    /// Meters per mile conversion
+    static let metersPerMile: Double = 1609.344
+
+    /// Nearby radius in meters
+    static var nearbyRadiusMeters: Double { nearbyRadiusMiles * metersPerMile }
+
+    // MARK: - Timeouts
+
+    /// Maximum time for performance/scale tests (5 minutes)
+    static let performanceTimeout: TimeInterval = 300.0
+
+    /// Maximum time before a test is considered hung (30 seconds)
+    static let hangTimeout: TimeInterval = 30.0
+
+    /// Standard async test timeout
+    static let standardTimeout: TimeInterval = 10.0
+
+    // MARK: - Performance Baselines
+    // These will be recorded after initial runs and updated
+
+    /// Baseline time for 500 games (to be determined)
+    static var baseline500Games: TimeInterval = 0
+
+    /// Baseline time for 2000 games (to be determined)
+    static var baseline2000Games: TimeInterval = 0
+
+    /// Baseline time for 10000 games (to be determined)
+    static var baseline10000Games: TimeInterval = 0
+
+    // MARK: - Driving Constraints
+
+    /// Default max driving hours per day (single driver)
+    static let defaultMaxDrivingHoursPerDay: Double = 8.0
+
+    /// Average driving speed (mph) for estimates
+    static let averageDrivingSpeedMPH: Double = 60.0
+
+    /// Max days lookahead for game transitions
+    static let maxDayLookahead: Int = 5
+
+    // MARK: - Brute Force Verification
+
+    /// Maximum number of stops for brute force verification
+    static let bruteForceMaxStops: Int = 8
+
+    // MARK: - Test Data Sizes
+
+    enum DataSize: Int {
+        case tiny = 5
+        case small = 50
+        case medium = 500
+        case large = 2000
+        case stress = 10000
+        case extreme = 50000
+    }
+
+    // MARK: - Geographic Constants
+
+    /// Earth radius in miles (for haversine)
+    static let earthRadiusMiles: Double = 3958.8
+
+    /// Earth circumference in miles
+    static let earthCircumferenceMiles: Double = 24901.0
+
+    // MARK: - Known Distances (for validation)
+
+    /// NYC to LA approximate distance in miles
+    static let nycToLAMiles: Double = 2451.0
+
+    /// Distance tolerance percentage for validation
+    static let distanceTolerancePercent: Double = 0.01 // 1%
+}