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/Views/CommunityEventDetailView.swift

@@ -0,0 +1,209 @@
+import SwiftUI
+
+struct CommunityEventDetailView: View {
+    let event: CommunityEvent
+    @StateObject private var viewModel = CommunityEventViewModel()
+
+    var body: some View {
+        ScrollView {
+            VStack(alignment: .leading, spacing: 16) {
+                eventHeader
+                eventInfoSection
+                eventDescription
+                rsvpSection
+                participantsSection
+            }
+            .padding(.horizontal)
+            .padding(.bottom, 32)
+        }
+        .navigationTitle(event.title)
+        .navigationBarTitleDisplayMode(.inline)
+        .onAppear {
+            Task {
+                await viewModel.selectEvent(id: event.id)
+            }
+        }
+    }
+
+    private var eventHeader: some View {
+        VStack(spacing: 12) {
+            HStack {
+                Image(systemName: event.eventType.icon)
+                    .font(.system(size: 40))
+                    .foregroundColor(event.eventType.color)
+                VStack(alignment: .leading, spacing: 4) {
+                    Text(event.eventType.displayName)
+                        .font(.title2)
+                        .fontWeight(.bold)
+                    if let distance = event.distanceKm {
+                        Text("\(distance) km \u2022 \(event.location)")
+                    } else {
+                        Text(event.location)
+                    }
+                    .font(.subheadline)
+                    .foregroundColor(.secondary)
+                }
+                Spacer()
+            }
+
+            Divider()
+
+            HStack(spacing: 20) {
+                infoItem(label: "Date", value: formatDate(event.startDate))
+                infoItem(label: "Participants", value: "\(event.participantCount)")
+                if let difficulty = event.difficulty {
+                    infoItem(label: "Difficulty", value: difficulty.displayName)
+                }
+            }
+        }
+        .padding()
+        .background(Color.secondary.opacity(0.1))
+        .cornerRadius(12)
+    }
+
+    private func infoItem(label: String, value: String) -> some View {
+        VStack(alignment: .leading, spacing: 2) {
+            Text(label)
+                .font(.caption)
+                .foregroundColor(.secondary)
+            Text(value)
+                .font(.subheadline)
+                .fontWeight(.medium)
+        }
+    }
+
+    private var eventInfoSection: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            Text("Event Details")
+                .font(.headline)
+            VStack(alignment: .leading, spacing: 6) {
+                detailRow(label: "Organizer", value: event.organizerName)
+                detailRow(label: "Location", value: event.location)
+                detailRow(label: "Start", value: formatDateTime(event.startDate))
+                detailRow(label: "End", value: formatDateTime(event.endDate))
+                if let max = event.maxParticipants {
+                    detailRow(label: "Capacity", value: "\(event.participantCount)/\(max)")
+                }
+            }
+        }
+    }
+
+    private func detailRow(label: String, value: String) -> some View {
+        HStack {
+            Text(label)
+                .font(.subheadline)
+                .foregroundColor(.secondary)
+                .frame(width: 100, alignment: .leading)
+            Text(value)
+                .font(.subheadline)
+                .fontWeight(.medium)
+        }
+    }
+
+    private var eventDescription: some View {
+        VStack(alignment: .leading, spacing: 4) {
+            Text("About This Event")
+                .font(.headline)
+            Text(event.description)
+                .font(.subheadline)
+                .foregroundColor(.secondary)
+        }
+    }
+
+    private var rsvpSection: some View {
+        VStack(alignment: .leading, spacing: 12) {
+            Text("Your RSVP")
+                .font(.headline)
+
+            HStack(spacing: 12) {
+                rsvpButton(title: "Going", icon: "checkmark.circle", status: .going, color: .green)
+                rsvpButton(title: "Maybe", icon: "questionmark.circle", status: .maybe, color: .orange)
+                rsvpButton(title: "Not Going", icon: "xmark.circle", status: .notGoing, color: .red)
+            }
+        }
+    }
+
+    private func rsvpButton(title: String, icon: String, status: RSVPStatus, color: Color) -> some View {
+        Button {
+            Task {
+                await viewModel.RSVP(eventId: event.id, status: status)
+            }
+        } label: {
+            VStack(spacing: 4) {
+                Image(systemName: event.rsvpStatus == status ? "\(icon).fill" : icon)
+                    .foregroundColor(event.rsvpStatus == status ? color : .secondary)
+                Text(title)
+                    .font(.caption)
+                    .foregroundColor(event.rsvpStatus == status ? color : .secondary)
+            }
+            .frame(maxWidth: .infinity)
+            .padding(.vertical, 8)
+            .background(event.rsvpStatus == status ? color.opacity(0.15) : Color.secondary.opacity(0.08))
+            .cornerRadius(8)
+        }
+    }
+
+    private var participantsSection: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            Text("Participants (\(event.participantCount))")
+                .font(.headline)
+
+            ForEach(viewModel.participants) { participant in
+                HStack(spacing: 12) {
+                    Circle()
+                        .fill(Color.secondary.opacity(0.2))
+                        .frame(width: 32, height: 32)
+                    Text(participant.name)
+                        .font(.subheadline)
+                    Spacer()
+                    Text(participant.rsvpStatus.rawValue.capitalized)
+                        .font(.caption)
+                        .foregroundColor(participant.rsvpStatus == .going ? .green : .secondary)
+                }
+            }
+        }
+    }
+
+    private func formatDate(_ date: Date) -> String {
+        let formatter = DateFormatter()
+        formatter.dateStyle = .medium
+        formatter.timeStyle = .none
+        return formatter.string(from: date)
+    }
+
+    private func formatDateTime(_ date: Date) -> String {
+        let formatter = DateFormatter()
+        formatter.dateStyle = .short
+        formatter.timeStyle = .short
+        return formatter.string(from: date)
+    }
+}
+
+#Preview {
+    NavigationView {
+        CommunityEventDetailView(event: sampleEvent)
+    }
+}
+
+private var sampleEvent: CommunityEvent {
+    CommunityEvent(
+        id: "1",
+        title: "Sunday Morning Group Run",
+        description: "Join us for a friendly morning run through the park. All paces welcome!",
+        eventType: .groupRun,
+        location: "Central Park",
+        latitude: 40.7851,
+        longitude: -73.9683,
+        startDate: Date().addingTimeInterval(7 * 24 * 3600),
+        endDate: Date().addingTimeInterval(7 * 24 * 3600 + 3600),
+        distanceKm: 10,
+        organizerId: "user1",
+        organizerName: "Running Club",
+        maxParticipants: 50,
+        participantCount: 23,
+        imageUrl: nil,
+        difficulty: .beginner,
+        rsvpStatus: .pending,
+        createdAt: Date()
+    )
+}