feat: add unified ItineraryItem model

Replaces CustomItineraryItem and TravelDayOverride with single model.
Supports game, travel, and custom item kinds.

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

SportsTime/Core/Models/Domain/ItineraryItem.swift

@@ -0,0 +1,124 @@
+import Foundation
+import CoreLocation
+
+/// Unified model for all itinerary items (games, travel, custom)
+struct ItineraryItem: Identifiable, Codable, Hashable {
+    let id: UUID
+    let tripId: UUID
+    var day: Int                    // 1-indexed day number
+    var sortOrder: Double           // Position within day (fractional)
+    var kind: ItemKind
+    var modifiedAt: Date
+
+    init(
+        id: UUID = UUID(),
+        tripId: UUID,
+        day: Int,
+        sortOrder: Double,
+        kind: ItemKind,
+        modifiedAt: Date = Date()
+    ) {
+        self.id = id
+        self.tripId = tripId
+        self.day = day
+        self.sortOrder = sortOrder
+        self.kind = kind
+        self.modifiedAt = modifiedAt
+    }
+}
+
+/// The type of itinerary item
+enum ItemKind: Codable, Hashable {
+    case game(gameId: String)
+    case travel(TravelInfo)
+    case custom(CustomInfo)
+}
+
+/// Travel-specific information
+struct TravelInfo: Codable, Hashable {
+    let fromCity: String
+    let toCity: String
+    var distanceMeters: Double?
+    var durationSeconds: Double?
+
+    var formattedDistance: String {
+        guard let meters = distanceMeters else { return "" }
+        let miles = meters / 1609.34
+        return String(format: "%.0f mi", miles)
+    }
+
+    var formattedDuration: String {
+        guard let seconds = durationSeconds else { return "" }
+        let hours = Int(seconds) / 3600
+        let minutes = (Int(seconds) % 3600) / 60
+        if hours > 0 {
+            return "\(hours)h \(minutes)m"
+        }
+        return "\(minutes)m"
+    }
+}
+
+/// Custom item information
+struct CustomInfo: Codable, Hashable {
+    var title: String
+    var icon: String
+    var time: Date?
+    var latitude: Double?
+    var longitude: Double?
+    var address: String?
+
+    var coordinate: CLLocationCoordinate2D? {
+        guard let lat = latitude, let lon = longitude else { return nil }
+        return CLLocationCoordinate2D(latitude: lat, longitude: lon)
+    }
+
+    var isMappable: Bool {
+        latitude != nil && longitude != nil
+    }
+}
+
+// MARK: - Convenience Properties
+
+extension ItineraryItem {
+    var isGame: Bool {
+        if case .game = kind { return true }
+        return false
+    }
+
+    var isTravel: Bool {
+        if case .travel = kind { return true }
+        return false
+    }
+
+    var isCustom: Bool {
+        if case .custom = kind { return true }
+        return false
+    }
+
+    var travelInfo: TravelInfo? {
+        if case .travel(let info) = kind { return info }
+        return nil
+    }
+
+    var customInfo: CustomInfo? {
+        if case .custom(let info) = kind { return info }
+        return nil
+    }
+
+    var gameId: String? {
+        if case .game(let id) = kind { return id }
+        return nil
+    }
+
+    /// Display title for the item
+    var displayTitle: String {
+        switch kind {
+        case .game(let gameId):
+            return "Game: \(gameId)"
+        case .travel(let info):
+            return "\(info.fromCity) → \(info.toCity)"
+        case .custom(let info):
+            return info.title
+        }
+    }
+}