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/ViewModels/CommunityEventViewModel.swift

@@ -0,0 +1,119 @@
+import Foundation
+import SwiftUI
+
+@MainActor
+class CommunityEventViewModel: ObservableObject {
+    @Published var events: [CommunityEvent] = []
+    @Published var selectedEvent: CommunityEvent?
+    @Published var participants: [EventParticipant] = []
+    @Published var isLoading: Bool = false
+    @Published var error: CommunityEventError?
+    @Published var filter: EventFilter = EventFilter()
+
+    private let service: CommunityEventServiceProtocol
+
+    init(service: CommunityEventServiceProtocol = CommunityEventService()) {
+        self.service = service
+    }
+
+    func fetchEvents() async {
+        isLoading = true
+        error = nil
+        defer { isLoading = false }
+
+        do {
+            events = try await service.listEvents(filter: filter)
+        } catch let error as CommunityEventError {
+            self.error = error
+        } catch {
+            print("Failed to fetch events: \(error)")
+        }
+    }
+
+    func selectEvent(id: String) async {
+        isLoading = true
+        error = nil
+        defer { isLoading = false }
+
+        do {
+            let result = try await service.getEvent(id: id)
+            selectedEvent = result.event
+            participants = result.participants
+            if let index = events.firstIndex(where: { $0.id == id }) {
+                events[index] = result.event
+                objectWillChange.send()
+            }
+        } catch let error as CommunityEventError {
+            self.error = error
+        } catch {
+            print("Failed to get event: \(error)")
+        }
+    }
+
+    func createEvent(request: CreateEventRequest) async -> CommunityEvent? {
+        isLoading = true
+        error = nil
+        defer { isLoading = false }
+
+        do {
+            let event = try await service.createEvent(request: request)
+            events.insert(event, at: 0)
+            objectWillChange.send()
+            return event
+        } catch let error as CommunityEventError {
+            self.error = error
+            return nil
+        } catch {
+            print("Failed to create event: \(error)")
+            return nil
+        }
+    }
+
+    func updateEvent(id: String, request: UpdateEventRequest) async {
+        isLoading = true
+        error = nil
+        defer { isLoading = false }
+
+        do {
+            let updatedEvent = try await service.updateEvent(id: id, request: request)
+            if let index = events.firstIndex(where: { $0.id == id }) {
+                events[index] = updatedEvent
+                objectWillChange.send()
+            }
+            if selectedEvent?.id == id {
+                selectedEvent = updatedEvent
+            }
+        } catch let error as CommunityEventError {
+            self.error = error
+        } catch {
+            print("Failed to update event: \(error)")
+        }
+    }
+
+    func RSVP(eventId: String, status: RSVPStatus) async {
+        do {
+            try await service.RSVP(eventId: eventId, status: status)
+            if let index = events.firstIndex(where: { $0.id == eventId }) {
+                events[index].rsvpStatus = status
+                objectWillChange.send()
+            }
+        } catch {
+            print("Failed to RSVP: \(error)")
+        }
+    }
+
+    var upcomingEvents: [CommunityEvent] {
+        events.filter { $0.isUpcoming }.sorted { $0.startDate < $1.startDate }
+    }
+
+    var ongoingEvents: [CommunityEvent] {
+        events.filter { $0.isOngoing }
+    }
+
+    var pastEvents: [CommunityEvent] {
+        events.filter { $0.isPast }.sorted { $0.endDate > $1.endDate }
+    }
+
+    var eventTypes: [EventType] { EventType.allCases }
+    var rsvpStatuses: [RSVPStatus] { RSVPStatus.allCases }
+}