Fix logout, share code display, loading states, and multi-user support

iOS Logout Fix:
- Use @EnvironmentObject in MainTabView and ProfileTabView
- Pass loginViewModel from LoginView to MainTabView
- Handle logout by dismissing main tab when isAuthenticated becomes false
- Logout button now properly returns user to login screen

Share Code UX:
- Clear share code on ManageUsers screen open (iOS & Android)
- Remove auto-loading of share codes
- User must explicitly generate code each time
- Improves security with fresh codes

Loading State Improvements:
- iOS ResidenceDetailView shows loading immediately on navigation
- Android ResidenceDetailScreen enhanced with "Loading residence..." text
- Better user feedback during API calls

Multi-User Support:
- Add isPrimaryOwner and userCount to ResidenceWithTasks model
- Update iOS toResidences() extension to include new fields
- Sync with backend API changes for shared user access

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

iosApp/iosApp/MainTabView.swift

@@ -1,7 +1,7 @@
 import SwiftUI
 
 struct MainTabView: View {
-    @StateObject private var loginViewModel = LoginViewModel()
+    @EnvironmentObject var loginViewModel: LoginViewModel
     @State private var selectedTab = 0
 
     var body: some View {
@@ -34,7 +34,7 @@ struct MainTabView: View {
 }
 
 struct ProfileTabView: View {
-    @StateObject private var loginViewModel = LoginViewModel()
+    @EnvironmentObject var loginViewModel: LoginViewModel
     @State private var showingProfileEdit = false
 
     var body: some View {