FRE-4665: Implement Phase 3 AI training plans and premium features

- Models: TrainingPlan, Race, FamilyPlan, BeginnerMode, CommunityEvent
- Services: 5 service layers with protocol-based architecture
- ViewModels: 5 view models with @MainActor ObservableObject pattern
- Views: 10 SwiftUI views for all Phase 3 features
- Updated README with full Phase 3 documentation

Co-Authored-By: Paperclip <noreply@paperclip.ing>

Lendair/Models/FamilyPlan.swift

@@ -0,0 +1,217 @@
+import Foundation
+import SwiftUI
+
+// MARK: - Family Plan
+
+struct FamilyPlan: Identifiable, Equatable, Codable {
+    let id: String
+    let ownerId: String
+    let ownerName: String
+    let members: [FamilyMember]
+    let maxMembers: Int
+    let subscriptionStatus: SubscriptionStatus
+    let renewalDate: Date?
+    let createdAt: Date
+
+    enum CodingKeys: String, CodingKey {
+        case id, ownerId, ownerName, members, maxMembers, subscriptionStatus, renewalDate, createdAt
+    }
+
+    init(
+        id: String,
+        ownerId: String,
+        ownerName: String,
+        members: [FamilyMember],
+        maxMembers: Int,
+        subscriptionStatus: SubscriptionStatus,
+        renewalDate: Date?,
+        createdAt: Date
+    ) {
+        self.id = id
+        self.ownerId = ownerId
+        self.ownerName = ownerName
+        self.members = members
+        self.maxMembers = maxMembers
+        self.subscriptionStatus = subscriptionStatus
+        self.renewalDate = renewalDate
+        self.createdAt = createdAt
+    }
+
+    static func == (lhs: FamilyPlan, rhs: FamilyPlan) -> Bool {
+        lhs.id == rhs.id
+    }
+
+    var availableSlots: Int {
+        maxMembers - members.count
+    }
+
+    var isActive: Bool {
+        subscriptionStatus == .active
+    }
+}
+
+// MARK: - Family Member
+
+struct FamilyMember: Identifiable, Equatable, Codable {
+    let id: String
+    let name: String
+    let email: String
+    let role: MemberRole
+    let joinedAt: Date
+    let avatarUrl: String?
+    var isPrimary: Bool
+    var totalDistanceKm: Double
+    var totalWorkouts: Int
+    var weeklyDistanceKm: Double
+    var weeklyWorkouts: Int
+
+    enum CodingKeys: String, CodingKey {
+        case id, name, email, role, joinedAt, avatarUrl, isPrimary, totalDistanceKm, totalWorkouts, weeklyDistanceKm, weeklyWorkouts
+    }
+
+    init(
+        id: String,
+        name: String,
+        email: String,
+        role: MemberRole,
+        joinedAt: Date,
+        avatarUrl: String?,
+        isPrimary: Bool,
+        totalDistanceKm: Double,
+        totalWorkouts: Int,
+        weeklyDistanceKm: Double,
+        weeklyWorkouts: Int
+    ) {
+        self.id = id
+        self.name = name
+        self.email = email
+        self.role = role
+        self.joinedAt = joinedAt
+        self.avatarUrl = avatarUrl
+        self.isPrimary = isPrimary
+        self.totalDistanceKm = totalDistanceKm
+        self.totalWorkouts = totalWorkouts
+        self.weeklyDistanceKm = weeklyDistanceKm
+        self.weeklyWorkouts = weeklyWorkouts
+    }
+
+    static func == (lhs: FamilyMember, rhs: FamilyMember) -> Bool {
+        lhs.id == rhs.id
+    }
+}
+
+// MARK: - Member Role
+
+enum MemberRole: String, CaseIterable, Codable {
+    case owner
+    case member
+    case pending
+
+    var displayName: String {
+        switch self {
+        case .owner: return "Owner"
+        case .member: return "Member"
+        case .pending: return "Pending"
+        }
+    }
+
+    var icon: String {
+        switch self {
+        case .owner: return "star.fill"
+        case .member: return "person.fill"
+        case .pending: return "person.crop.circle.badge.exclamationmark"
+        }
+    }
+}
+
+// MARK: - Subscription Status
+
+enum SubscriptionStatus: String, CaseIterable, Codable {
+    case active
+    case expired
+    case cancelled
+    case pending
+
+    var displayName: String {
+        switch self {
+        case .active: return "Active"
+        case .expired: return "Expired"
+        case .cancelled: return "Cancelled"
+        case .pending: return "Pending"
+        }
+    }
+
+    var color: Color {
+        switch self {
+        case .active: return .green
+        case .expired: return .red
+        case .cancelled: return .orange
+        case .pending: return .yellow
+        }
+    }
+}
+
+// MARK: - Family Leaderboard Entry
+
+struct FamilyLeaderboardEntry: Identifiable, Codable {
+    let id: String
+    let memberId: String
+    let memberName: String
+    let avatarUrl: String?
+    let metric: LeaderboardMetric
+    let value: Double
+    let rank: Int
+}
+
+// MARK: - Leaderboard Metric
+
+enum LeaderboardMetric: String, CaseIterable, Codable {
+    case distance
+    case workouts
+    case streak
+
+    var displayName: String {
+        switch self {
+        case .distance: return "Distance"
+        case .workouts: return "Workouts"
+        case .streak: return "Streak"
+        }
+    }
+
+    var unit: String {
+        switch self {
+        case .distance: return "km"
+        case .workouts: return ""
+        case .streak: return "days"
+        }
+    }
+}
+
+// MARK: - Invite Member Request
+
+struct InviteMemberRequest: Encodable {
+    let email: String
+    let name: String
+}
+
+// MARK: - API Response Types
+
+struct FamilyPlanDetailResponse: Decodable {
+    let plan: FamilyPlan
+}
+
+struct InviteMemberResponse: Decodable {
+    let success: Bool
+    let invitationId: String
+    let memberEmail: String
+}
+
+struct RemoveMemberResponse: Decodable {
+    let success: Bool
+    let memberId: String
+}
+
+struct FamilyLeaderboardResponse: Decodable {
+    let entries: [FamilyLeaderboardEntry]
+    let metric: LeaderboardMetric
+}