feat: add Follow Team Mode (Scenario D) for road trip planning

Adds a new planning mode that lets users follow a team's schedule
(home + away games) and builds multi-city routes accordingly.

Key changes:
- New ScenarioDPlanner with team filtering and route generation
- Team picker UI with sport grouping and search
- Fix TravelEstimator 5-day limit (was 2-day) for cross-country routes
- Fix DateInterval end boundary to include games on last day
- Comprehensive test suite covering edge cases:
  - Multi-city routes with adequate/insufficient time
  - Optimal game selection per city for feasibility
  - 5-day driving segment limits
  - Multiple driver scenarios

Enables trips like Houston → Chicago → Anaheim following the Astros.

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

SportsTime/Planning/Models/PlanningModels.swift

@@ -15,6 +15,7 @@ enum PlanningScenario: Equatable {
     case scenarioA  // Date range only
     case scenarioB  // Selected games + date range
     case scenarioC  // Start + end locations
+    case scenarioD  // Follow team schedule
 }
 
 // MARK: - Planning Failure
@@ -29,6 +30,7 @@ struct PlanningFailure: Error {
         case noValidRoutes
         case missingDateRange
         case missingLocations
+        case missingTeamSelection
         case dateRangeViolation(games: [Game])
         case drivingExceedsLimit
         case cannotArriveInTime
@@ -43,6 +45,7 @@ struct PlanningFailure: Error {
                  (.noValidRoutes, .noValidRoutes),
                  (.missingDateRange, .missingDateRange),
                  (.missingLocations, .missingLocations),
+                 (.missingTeamSelection, .missingTeamSelection),
                  (.drivingExceedsLimit, .drivingExceedsLimit),
                  (.cannotArriveInTime, .cannotArriveInTime),
                  (.travelSegmentMissing, .travelSegmentMissing),
@@ -70,6 +73,7 @@ struct PlanningFailure: Error {
         case .noValidRoutes: return "No valid routes could be constructed"
         case .missingDateRange: return "Date range is required"
         case .missingLocations: return "Start and end locations are required"
+        case .missingTeamSelection: return "Select a team to follow"
         case .dateRangeViolation(let games):
             return "\(games.count) selected game(s) fall outside the date range"
         case .drivingExceedsLimit: return "Driving time exceeds daily limit"
@@ -512,9 +516,15 @@ struct PlanningRequest {
     }
 
     /// Date range as DateInterval
+    /// Note: End date is extended to end-of-day to include all games on the last day,
+    /// since DateInterval.contains() uses exclusive end boundary.
     var dateRange: DateInterval? {
         guard preferences.endDate > preferences.startDate else { return nil }
-        return DateInterval(start: preferences.startDate, end: preferences.endDate)
+        // Extend end date to end of day (23:59:59) to include games on the last day
+        let calendar = Calendar.current
+        let endOfDay = calendar.date(bySettingHour: 23, minute: 59, second: 59, of: preferences.endDate)
+            ?? preferences.endDate
+        return DateInterval(start: preferences.startDate, end: endOfDay)
     }
 
     /// First must-stop location (if any)