Migrate iOS app to system colors and improve UI/UX

- Remove AppColors struct, migrate to iOS system colors throughout
- Redesign ContractorFormSheet to use native SwiftUI Form components
- Add color-coded icons to contractor form sections
- Improve dark mode contrast for task cards
- Add background colors to document detail fields
- Fix text alignment issues in ContractorDetailView
- Make task completion lists expandable/collapsible by default
- Clear app badge on launch and when app becomes active
- Update button styling with proper gradients and shadows
- Improve form field focus states and accessibility

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

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

iosApp/iosApp/Residence/ResidencesListView.swift

@@ -8,7 +8,7 @@ struct ResidencesListView: View {
 
     var body: some View {
         ZStack {
-            AppColors.background
+            Color(.systemGroupedBackground)
                 .ignoresSafeArea()
 
             if viewModel.myResidences == nil && viewModel.isLoading {
@@ -17,7 +17,7 @@ struct ResidencesListView: View {
                         .scaleEffect(1.2)
                     Text("Loading properties...")
                         .font(.body)
-                        .foregroundColor(AppColors.textSecondary)
+                        .foregroundColor(Color(.secondaryLabel))
                 }
             } else if let error = viewModel.errorMessage {
                 ErrorView(message: error) {
@@ -39,10 +39,10 @@ struct ResidencesListView: View {
                                 VStack(alignment: .leading, spacing: AppSpacing.xxs) {
                                     Text("Your Properties")
                                         .font(.title3.weight(.semibold))
-                                        .foregroundColor(AppColors.textPrimary)
+                                        .foregroundColor(Color(.label))
                                     Text("\(response.residences.count) \(response.residences.count == 1 ? "property" : "properties")")
                                         .font(.callout)
-                                        .foregroundColor(AppColors.textSecondary)
+                                        .foregroundColor(Color(.secondaryLabel))
                                 }
                                 Spacer()
                             }
@@ -77,7 +77,7 @@ struct ResidencesListView: View {
                 }) {
                     Image(systemName: "person.badge.plus")
                         .font(.system(size: 18, weight: .semibold))
-                        .foregroundColor(AppColors.primary)
+                        .foregroundColor(.blue)
                 }
 
                 Button(action: {
@@ -85,7 +85,7 @@ struct ResidencesListView: View {
                 }) {
                     Image(systemName: "plus.circle.fill")
                         .font(.system(size: 22, weight: .semibold))
-                        .foregroundColor(AppColors.primary)
+                        .foregroundColor(.blue)
                 }
             }
         }