refactor: notifications and settings view models; enhance login and registration UI

Mayday/Views/UIKit/AppBackground.swift

@@ -0,0 +1,20 @@
+import SwiftUI
+
+struct AppBackgroundModifier: ViewModifier {
+    func body(content: Content) -> some View {
+        content.background(
+            LinearGradient(
+                colors: [Color(.systemGroupedBackground), Color.red.opacity(0.08)],
+                startPoint: .top,
+                endPoint: .bottom
+            )
+            .ignoresSafeArea()
+        )
+    }
+}
+
+extension View {
+    func appBackground() -> some View {
+        modifier(AppBackgroundModifier())
+    }
+}

Mayday/Views/UIKit/AppSecureField.swift

@@ -0,0 +1,25 @@
+import SwiftUI
+
+struct AppSecureField: View {
+    let title: LocalizedStringKey
+    let icon: String
+    @Binding var text: String
+
+    var body: some View {
+        HStack(spacing: 10) {
+            Image(systemName: icon)
+                .foregroundStyle(.secondary)
+                .frame(width: 18)
+
+            SecureField(title, text: $text)
+        }
+        .padding(.horizontal, 14)
+        .padding(.vertical, 14)
+        .background(Color(.secondarySystemBackground))
+        .clipShape(RoundedRectangle(cornerRadius: 14, style: .continuous))
+        .overlay(
+            RoundedRectangle(cornerRadius: 14, style: .continuous)
+                .stroke(Color.primary.opacity(0.08), lineWidth: 1)
+        )
+    }
+}

Mayday/Views/UIKit/AppTextField.swift

@@ -0,0 +1,25 @@
+import SwiftUI
+
+struct AppTextField: View {
+    let title: LocalizedStringKey
+    let icon: String
+    @Binding var text: String
+
+    var body: some View {
+        HStack(spacing: 10) {
+            Image(systemName: icon)
+                .foregroundStyle(.secondary)
+                .frame(width: 18)
+
+            TextField(title, text: $text)
+        }
+        .padding(.horizontal, 14)
+        .padding(.vertical, 14)
+        .background(Color(.secondarySystemBackground))
+        .clipShape(RoundedRectangle(cornerRadius: 14, style: .continuous))
+        .overlay(
+            RoundedRectangle(cornerRadius: 14, style: .continuous)
+                .stroke(Color.primary.opacity(0.08), lineWidth: 1)
+        )
+    }
+}

Mayday/Views/UIKit/CardContainer.swift

@@ -0,0 +1,22 @@
+import SwiftUI
+
+struct CardContainerModifier: ViewModifier {
+    func body(content: Content) -> some View {
+        content
+            .padding(.horizontal, 20)
+            .padding(.vertical, 24)
+            .background(Color(.systemBackground).opacity(0.8))
+            .clipShape(RoundedRectangle(cornerRadius: 28, style: .continuous))
+            .overlay(
+                RoundedRectangle(cornerRadius: 28, style: .continuous)
+                    .stroke(Color.primary.opacity(0.06), lineWidth: 1)
+            )
+            .padding(16)
+    }
+}
+
+extension View {
+    func cardContainer() -> some View {
+        modifier(CardContainerModifier())
+    }
+}

Mayday/Views/UIKit/NotificationIconView.swift

@@ -0,0 +1,47 @@
+import SwiftUI
+
+enum NotificationSeverity: String {
+    case critical
+    case warning
+    case info
+    case success
+
+    var icon: String {
+        switch self {
+        case .critical: return "exclamationmark.triangle.fill"
+        case .warning:  return "exclamationmark.circle.fill"
+        case .info:     return "info.circle.fill"
+        case .success:  return "checkmark.seal.fill"
+        }
+    }
+
+    var color: Color {
+        switch self {
+        case .critical: return .red
+        case .warning:  return .orange
+        case .info:     return .blue
+        case .success:  return .green
+        }
+    }
+
+    init(from metadata: [String: String]?) {
+        let raw = metadata?["severity"]?.lowercased() ?? ""
+        self = NotificationSeverity(rawValue: raw) ?? .info
+    }
+}
+
+struct NotificationIconView: View {
+    let severity: NotificationSeverity
+    let isActive: Bool
+
+    var body: some View {
+        ZStack {
+            Circle()
+                .fill(isActive ? .white.opacity(0.25) : severity.color.opacity(0.12))
+                .frame(width: 40, height: 40)
+            Image(systemName: severity.icon)
+                .font(.body)
+                .foregroundStyle(isActive ? .white : severity.color)
+        }
+    }
+}

Mayday/Views/UIKit/OTPDigitField.swift

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+import SwiftUI
+import UIKit
+
+struct OTPDigitField: UIViewRepresentable {
+    @Binding var text: String
+    let isFocused: Bool
+    let onFocus: () -> Void
+    let onInsert: () -> Void
+    let onDeleteWhenEmpty: () -> Void
+    let onPaste: ([String]) -> Void
+
+    func makeUIView(context: Context) -> BackspaceAwareTextField {
+        let textField = BackspaceAwareTextField()
+        textField.delegate = context.coordinator
+        textField.keyboardType = .numberPad
+        textField.textAlignment = .center
+        textField.font = UIFont.systemFont(ofSize: 24, weight: .bold)
+        textField.textContentType = .oneTimeCode
+        textField.onDeleteWhenEmpty = {
+            onDeleteWhenEmpty()
+        }
+        textField.addTarget(context.coordinator, action: #selector(Coordinator.editingChanged(_:)), for: .editingChanged)
+        return textField
+    }
+
+    func updateUIView(_ uiView: BackspaceAwareTextField, context: Context) {
+        if uiView.text != text {
+            uiView.text = text
+        }
+
+        if isFocused && !uiView.isFirstResponder {
+            DispatchQueue.main.async {
+                uiView.becomeFirstResponder()
+            }
+        }
+    }
+
+    func makeCoordinator() -> Coordinator {
+        Coordinator(parent: self)
+    }
+
+    final class Coordinator: NSObject, UITextFieldDelegate {
+        var parent: OTPDigitField
+
+        init(parent: OTPDigitField) {
+            self.parent = parent
+        }
+
+        func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {
+            parent.onFocus()
+            return true
+        }
+
+        func textFieldDidBeginEditing(_ textField: UITextField) {
+            parent.onFocus()
+        }
+
+        func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
+            if string.isEmpty {
+                return true
+            }
+
+            let digits = string.filter { $0.isNumber }
+            guard !digits.isEmpty else {
+                return false
+            }
+
+            if digits.count > 1 {
+                parent.onPaste(digits.map(String.init))
+                return false
+            }
+
+            parent.text = String(digits.prefix(1))
+            parent.onInsert()
+            return false
+        }
+
+        @objc
+        func editingChanged(_ textField: UITextField) {
+            let digitsOnly = (textField.text ?? "").filter { $0.isNumber }
+            let single = String(digitsOnly.prefix(1))
+            if textField.text != single {
+                textField.text = single
+            }
+            parent.text = single
+        }
+    }
+}
+
+final class BackspaceAwareTextField: UITextField {
+    var onDeleteWhenEmpty: (() -> Void)?
+
+    override func deleteBackward() {
+        let wasEmpty = (text ?? "").isEmpty
+        super.deleteBackward()
+        if wasEmpty {
+            onDeleteWhenEmpty?()
+        }
+    }
+}