feat: clone Opal's rules feature with hard block enforcement

Rebuild the app around recurring screen-time blocking rules modeled on
Opal's My Apps tab:

- Onboarding with FamilyControls Screen Time authorization
- Apps home with Blocked Apps tiles and live rule cards
- New Rule sheet: Schedule/Time Limit/Open Limit types + preset gallery
- Rule editors: time windows (incl. overnight), day picker, app selection
  via FamilyActivityPicker (Block/Allow Only), rename, Hold to Commit
- Hard Mode: active hard rules cannot be edited, disabled, deleted, or
  unblocked until their window ends; soft rules pause until next window
- Shield enforcement through per-rule ManagedSettingsStore + RuleEnforcer
- 73 unit tests (Swift Testing) + 16 UI tests (XCUITest) with launch-arg
  harness for in-memory storage, mocked authorization, seeded scenarios
- docs/RULES_FEATURE_SPEC.md: spec derived from the reference recording

Known gap: background window transitions and time/open-limit thresholds
need a DeviceActivityMonitor extension; shields currently sync while the
app is running.

Severed/Services/LaunchConfiguration.swift

@@ -0,0 +1,45 @@
+//
+//  LaunchConfiguration.swift
+//  Severed
+//
+
+import Foundation
+
+/// Launch-argument configuration used by UI tests: in-memory storage, mocked
+/// Screen Time authorization, forced onboarding state, and seeded scenarios.
+struct LaunchConfiguration: Equatable {
+    enum SeedScenario: String {
+        /// One actively blocking rule ("Work Time") and one upcoming rule ("Sleep").
+        case standard
+        /// An actively blocking Hard Mode rule ("Locked In") plus an upcoming rule.
+        case hardModeActive = "hard-mode-active"
+    }
+
+    var isUITesting = false
+    /// Forces the onboarding-completed flag at launch. Nil leaves stored state alone.
+    var onboardingCompleted: Bool?
+    var seedScenario: SeedScenario?
+
+    static let uiTestingFlag = "-ui-testing"
+    static let onboardingCompletedFlag = "-onboarding-completed"
+    static let onboardingRequiredFlag = "-onboarding-required"
+    static let seedScenarioPrefix = "-seed-scenario="
+
+    static func parse(arguments: [String]) -> LaunchConfiguration {
+        var config = LaunchConfiguration()
+        config.isUITesting = arguments.contains(uiTestingFlag)
+        if arguments.contains(onboardingCompletedFlag) {
+            config.onboardingCompleted = true
+        } else if arguments.contains(onboardingRequiredFlag) {
+            config.onboardingCompleted = false
+        }
+        if let seedArgument = arguments.first(where: { $0.hasPrefix(seedScenarioPrefix) }) {
+            config.seedScenario = SeedScenario(
+                rawValue: String(seedArgument.dropFirst(seedScenarioPrefix.count))
+            )
+        }
+        return config
+    }
+
+    static let current = parse(arguments: ProcessInfo.processInfo.arguments)
+}