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/KordantWidgets/WidgetConfigurationIntent.swift

@@ -0,0 +1,51 @@
+import AppIntents
+import WidgetKit
+
+/// Severity filter for widget alert display.
+enum AlertSeverityFilter: String, AppEnum {
+    case all
+    case critical
+    case high
+
+    static var typeDisplayRepresentation: TypeDisplayRepresentation = "Alert Severity"
+
+    static var caseDisplayRepresentations: [AlertSeverityFilter: DisplayRepresentation] = [
+        .all: DisplayRepresentation(
+            title: "All Alerts",
+            subtitle: "Show alerts of all severity levels"
+        ),
+        .critical: DisplayRepresentation(
+            title: "Critical Only",
+            subtitle: "Only show critical alerts"
+        ),
+        .high: DisplayRepresentation(
+            title: "High & Critical",
+            subtitle: "Only show high and critical alerts"
+        ),
+    ]
+
+    /// Returns whether an alert with the given severity string passes this filter.
+    func matches(severity: String) -> Bool {
+        switch self {
+        case .all:
+            return true
+        case .critical:
+            return severity == "critical"
+        case .high:
+            return severity == "critical" || severity == "high"
+        }
+    }
+}
+
+/// Configuration intent for Kordant widgets.
+/// Allows users to filter alerts by severity from the widget gallery.
+struct KordantWidgetConfigurationIntent: WidgetConfigurationIntent {
+    static var title: LocalizedStringResource = "Widget Configuration"
+    static var description: LocalizedStringResource = "Choose which alerts to display on your widget."
+
+    @Parameter(
+        title: "Severity Filter",
+        default: .all
+    )
+    var severityFilter: AlertSeverityFilter
+}