feat: Implement NotificationsView component for Lendair iOS

- Create NotificationsView.swift with SwiftUI List and pull-to-refresh
- Create NotificationRowView.swift for individual notification items
- Create NotificationsViewModel.swift with MVVM pattern
- Implement empty state view for no notifications
- Add mark-as-read and mark-all-as-read functionality
- Support notification types: loan approved/rejected, payment received/due, new lender, system updates
- Add toolbar action for marking all notifications as read
- Include README.md with architecture documentation and integration guide

Next: Connect tRPC notifications router for data fetching

Lendair/Views/NotificationRowView.swift

@@ -0,0 +1,89 @@
+import SwiftUI
+
+struct NotificationRowView: View {
+    let notification: NotificationItem
+    
+    var body: some View {
+        HStack(spacing: 12) {
+            // Notification icon
+            Image(systemName: notification.type.icon)
+                .font(.system(size: 24))
+                .foregroundColor(notification.type.color)
+                .accessibilityLabel(notification.type.rawValue)
+            
+            // Notification content
+            VStack(alignment: .leading, spacing: 4) {
+                Text(notification.title)
+                    .font(.headline)
+                    .foregroundColor(.primary)
+                
+                Text(notification.message)
+                    .font(.subheadline)
+                    .foregroundColor(.secondary)
+                    .lineLimit(2)
+            }
+            
+            Spacer()
+            
+            // Timestamp and read indicator
+            VStack(alignment: .trailing, spacing: 4) {
+                if !notification.isRead {
+                    Image(systemName: "circle.fill")
+                        .font(.system(size: 8))
+                        .foregroundColor(.blue)
+                }
+                
+                Text(formatTimestamp(notification.createdAt))
+                    .font(.caption)
+                    .foregroundColor(.secondary)
+            }
+        }
+        .padding(.vertical, 8)
+        .contentShape(Rectangle())
+    }
+    
+    private func formatTimestamp(_ date: Date) -> String {
+        let formatter = RelativeDateTimeFormatter()
+        formatter.unitsStyle = .abbreviated
+        return formatter.localizedString(for: date, relativeTo: Date())
+    }
+}
+
+#Preview {
+    List {
+        NotificationRowView(
+            notification: NotificationItem(
+                id: "1",
+                type: .loanApproved,
+                title: "Loan Approved",
+                message: "Your loan application for $500 has been approved by Sarah Johnson.",
+                createdAt: Date().addingTimeInterval(-3600),
+                isRead: false
+            )
+        )
+        
+        NotificationRowView(
+            notification: NotificationItem(
+                id: "2",
+                type: .paymentDue,
+                title: "Payment Due Soon",
+                message: "Your payment of $150 is due in 3 days.",
+                createdAt: Date().addingTimeInterval(-86400 * 2),
+                isRead: true
+            )
+        )
+        
+        NotificationRowView(
+            notification: NotificationItem(
+                id: "3",
+                type: .paymentReceived,
+                title: "Payment Received",
+                message: "You received a payment of $75 from Michael Chen.",
+                createdAt: Date().addingTimeInterval(-86400 * 5),
+                isRead: false
+            )
+        )
+    }
+    .listStyle(.insetGrouped)
+    .previewDisplayName("Notification Row Preview")
+}