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.

Co-Authored-By: Claude <noreply@anthropic.com>

Severed/Views/Apps/RuleCardView.swift

@@ -0,0 +1,90 @@
+//
+//  RuleCardView.swift
+//  Severed
+//
+
+import SwiftUI
+
+/// A rule tile in the home screen's Rules carousel: icon pair, live status,
+/// name, and the block summary. Active rules glow green.
+struct RuleCardView: View {
+    let rule: BlockingRule
+    let now: Date
+
+    private var status: RuleStatus { rule.status(at: now) }
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 12) {
+            RuleIconPair(kind: rule.kind, isActive: status.isActive)
+            statusView
+            Text(rule.name)
+                .font(.system(size: 17, weight: .semibold))
+                .foregroundStyle(.white)
+                .lineLimit(1)
+            HStack(spacing: 5) {
+                Text(rule.selectionMode.displayName)
+                    .foregroundStyle(Theme.textSecondary)
+                Text(blockSummary)
+                    .foregroundStyle(Theme.textTertiary)
+            }
+            .font(.system(size: 13))
+        }
+        .padding(16)
+        .frame(width: 172, alignment: .leading)
+        .background(cardBackground, in: RoundedRectangle(cornerRadius: 22))
+        .overlay(
+            RoundedRectangle(cornerRadius: 22)
+                .strokeBorder(
+                    status.isActive ? Theme.accent.opacity(0.35) : .white.opacity(0.08),
+                    lineWidth: 1
+                )
+        )
+    }
+
+    @ViewBuilder
+    private var statusView: some View {
+        switch status {
+        case .active:
+            Text(status.label(relativeTo: now))
+                .font(.system(size: 12, weight: .semibold))
+                .foregroundStyle(.black)
+                .padding(.horizontal, 10)
+                .padding(.vertical, 5)
+                .background(Theme.accent, in: Capsule())
+                .accessibilityIdentifier("ruleStatus-\(rule.name)")
+        case .paused, .disabled, .dormant, .upcoming:
+            Text(statusText)
+                .font(.system(size: 13, weight: .medium))
+                .foregroundStyle(Theme.textSecondary)
+                .padding(.vertical, 5)
+                .accessibilityIdentifier("ruleStatus-\(rule.name)")
+        }
+    }
+
+    private var statusText: String {
+        switch rule.kind {
+        case .schedule:
+            status.label(relativeTo: now)
+        case .timeLimit:
+            rule.isEnabled ? "\(rule.dailyLimitMinutes)m / day" : "Disabled"
+        case .openLimit:
+            rule.isEnabled ? "\(rule.maxOpens) opens / day" : "Disabled"
+        }
+    }
+
+    private var blockSummary: String {
+        rule.selectionCount == 1 ? "· 1 app" : "· \(rule.selectionCount) apps"
+    }
+
+    private var cardBackground: some ShapeStyle {
+        if status.isActive {
+            return AnyShapeStyle(
+                LinearGradient(
+                    colors: [Theme.activeCardTop, Theme.activeCardBottom],
+                    startPoint: .top, endPoint: .bottom
+                )
+            )
+        }
+        return AnyShapeStyle(Theme.surface)
+    }
+}