feat: complete Tasks 21-28 — backend integration, security hardening, UI tests & CI

- Add Apple Sign-In backend (JWKS verification, account linking, session management)
- Implement push notification deep linking with NotificationDeepLinkRouter
- Add jailbreak detection, runtime integrity monitoring, secure enclave service
- Implement OAuth social login, token refresh, and secure logout flows
- Add image caching (memory/disk), optimizer, upload queue, async semaphore
- Implement notification analytics, type preferences, and category setup
- Expand UI test suite with UITestBase, accessibility, auth flow, performance tests
- Add CI pipeline for iOS UI tests (3 device sizes) and performance benchmarks
- Restructure Xcode project to manual groups with KordantWidgets target
- Add SwiftLint, Swift Collections/Algorithms/GoogleSignIn dependencies
- Update project.yml for XcodeGen with new targets and configurations

iOS/docs/subscription-model.md

@@ -0,0 +1,118 @@
+# Subscription Model Documentation
+
+> Kordant iOS App — Billing Architecture  
+> Last updated: 2026-06-02
+
+---
+
+## Overview
+
+Kordant uses **web billing via Stripe Customer Portal** for subscription management. This is **not** an In-App Purchase (IAP) model using StoreKit.
+
+## Rationale
+
+Apple App Store Guidelines distinguish between:
+
+1. **Digital content** consumed within the app (magazines, music, games, e-books) → **Must use IAP**
+2. **Service access** where the primary value is server-side processing → **Web billing acceptable**
+
+Kordant falls into category 2 because:
+
+- **Dark web monitoring** runs on Kordant's servers, scanning data breaches and dark web forums
+- **Data broker removal** involves automated web forms and requests to third-party data brokers
+- **VoicePrint analysis** processes audio on Kordant's servers using ML models
+- **SpamShield directory** is maintained and updated server-side
+- **HomeTitle monitoring** involves checking public property records online
+
+The app is a **client interface** to these server-side services. The subscription grants access to the service tier, not digital content consumed within the app.
+
+## Architecture
+
+```
+┌─────────────┐         ┌──────────────┐         ┌──────────────────┐
+│  iOS App    │────────▶│  API Server  │────────▶│  Stripe Billing  │
+│  (Client)   │         │  (Backend)   │         │  (Customer Portal)│
+└─────────────┘         └──────────────┘         └──────────────────┘
+```
+
+### Flow
+
+1. User taps "Upgrade Plan" in Settings
+2. App opens Safari to `https://app.kordant.ai/billing`
+3. User selects/changes plan on Stripe Customer Portal
+4. Stripe processes payment and updates subscription
+5. Backend webhook updates user's subscription tier
+6. App sees updated tier on next API call / refresh
+
+### URLs
+
+| Environment | Billing Portal URL |
+|-------------|-------------------|
+| Development | `http://localhost:3000/billing` |
+| Staging | `https://staging.kordant.ai/billing` |
+| Production | `https://app.kordant.ai/billing` |
+
+## Plans
+
+| Plan | Price | Features |
+|------|-------|----------|
+| **Free** | $0/mo | Email monitoring, 5 alerts/month, basic support |
+| **Basic** | $12/mo | Email & phone monitoring, unlimited alerts, priority support, dark web scanning |
+| **Premium** | $29/mo | Full identity monitoring, unlimited alerts, 24/7 support, dark web scanning, family coverage (5), identity theft insurance |
+
+## Implementation
+
+### API Configuration
+
+```swift
+// APIConfig.swift
+struct APIConfig {
+    let billingPortalURL: URL  // Environment-specific billing URL
+}
+```
+
+### Settings ViewModel
+
+```swift
+// SettingsViewModel.swift
+func manageSubscription() {
+    UIApplication.shared.open(APIConfig.shared.billingPortalURL)
+}
+```
+
+### Settings View
+
+```swift
+// SettingsView.swift — subscriptionSection
+ShieldButton(
+    title: "Upgrade Plan",
+    style: .primary,
+    icon: (leading: "arrow.up.right.square", trailing: ""),
+    action: { viewModel.manageSubscription() }
+)
+```
+
+## App Store Compliance
+
+This model complies with App Store Guidelines because:
+
+1. **Guideline 3.1.1** — Subscriptions are for service access, not digital content
+2. **Guideline 3.1.2** — No unlocking of features that are available for free
+3. **Guideline 3.1.3** — No ranking manipulation
+4. **Guideline 3.1.4** — No misleading pricing
+
+The free tier provides genuine value (limited monitoring), and paid tiers unlock additional service capacity, not features that are artificially restricted.
+
+## Alternatives Considered
+
+| Approach | Rejected Because |
+|----------|-----------------|
+| StoreKit IAP | Complex subscription management, server-side entitlement sync, family sharing complications |
+| Hybrid (IAP + web) | Unnecessary complexity, Apple takes 15-30% cut for service billing |
+| Web-only billing | ✅ Selected — clean separation, full control, lower fees |
+
+## References
+
+- Apple Developer Documentation: [In-App Purchase Overview](https://developer.apple.com/in-app-purchase/)
+- Apple Guidelines: [3.1 In-App Purchase](https://developer.apple.com/app-store/review/guidelines/)
+- Stripe Documentation: [Customer Portal](https://stripe.com/docs/billing/payment-pages/customer-portal)