feat: enforce time and open limits in the background via Screen Time extensions

- Shared/ layer compiled into the app and three new extension targets:
  rule snapshots in the app group, the usage ledger, monitoring-plan
  naming, and LimitEnforcement (shared, unit-tested event reactions)
- RuleScheduler mirrors rules to the app group and reconciles
  DeviceActivity monitoring: one daily 00:00-23:59 activity per limit
  rule, with a cumulative usage-threshold event per budget minute for
  time limits; activities restart only when their configuration changes
  (a restart resets threshold accounting)
- OpenAppLockMonitor (DeviceActivityMonitor): midnight budget resets,
  records usage minutes, shields at the budget, re-shields when a
  granted open session ends
- OpenAppLockShieldConfig: open-limit shields show 'Opened X of N times
  today' with an 'Open (Y left)' secondary button
- OpenAppLockShieldAction: an Open press spends one open, lifts the
  rule's shield, and starts the ~15-minute one-shot session
- extensions are classic NSExtension app extensions (the ExtensionKit
  product type expects an @main entry and made the app fail to install);
  shield-store tracking moved to app-group defaults so the app and
  extensions see one consistent set
- maps iOS 26's new .approvedWithDataAccess authorization status to
  approved (it previously fell through @unknown default to notDetermined)
- shares the OpenAppLock scheme (Xcode dropped the autocreated one when
  targets were added)

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

Shared/AppGroup.swift

@@ -0,0 +1,19 @@
+//
+//  AppGroup.swift
+//  OpenAppLock
+//
+
+import Foundation
+
+/// The app group shared by the app and its Screen Time extensions. Usage
+/// tracking and rule snapshots live in its UserDefaults suite so the
+/// DeviceActivity monitor and shield extensions can read and write them.
+enum AppGroup {
+    static let identifier = "group.dev.bchen.OpenAppLock"
+
+    /// Shared defaults; falls back to standard defaults when the group
+    /// container is unavailable (e.g. entitlement not provisioned yet).
+    static var defaults: UserDefaults {
+        UserDefaults(suiteName: identifier) ?? .standard
+    }
+}

Shared/LimitEnforcement.swift

@@ -0,0 +1,98 @@
+//
+//  LimitEnforcement.swift
+//  OpenAppLock
+//
+
+import Foundation
+
+/// Shared reactions to Screen Time events for limit rules, driven by the
+/// snapshot store and usage ledger. The DeviceActivity monitor and shield
+/// extensions call these; keeping the logic here makes it unit-testable from
+/// the app target.
+struct LimitEnforcement {
+    let snapshots: RuleSnapshotStore
+    let ledger: UsageLedger
+    let shields: ShieldApplying
+
+    /// Midnight (or monitoring start): fresh budgets. Open-limit rules are
+    /// proactively shielded on enabled days so the shield can count opens;
+    /// time-limit rules start the day unshielded.
+    func handleDayStart(ruleID: UUID, now: Date = .now, calendar: Calendar = .current) {
+        guard let snapshot = snapshots.snapshot(for: ruleID), snapshot.isEnabled,
+              !snapshot.isPaused(at: now)
+        else { return }
+        let usage = ledger.usage(for: ruleID, onDayContaining: now, calendar: calendar)
+        switch snapshot.kind {
+        case .schedule:
+            break
+        case .openLimit:
+            if snapshot.isScheduledToday(at: now, calendar: calendar) {
+                shield(snapshot)
+            } else {
+                shields.clearShield(ruleID: ruleID)
+            }
+        case .timeLimit:
+            if snapshot.limitReached(given: usage),
+               snapshot.isScheduledToday(at: now, calendar: calendar) {
+                shield(snapshot)
+            } else {
+                shields.clearShield(ruleID: ruleID)
+            }
+        }
+    }
+
+    /// A cumulative usage checkpoint fired for a time-limit rule.
+    func handleUsageMinutes(
+        _ minutes: Int, ruleID: UUID, now: Date = .now, calendar: Calendar = .current
+    ) {
+        ledger.recordMinutesUsed(minutes, for: ruleID, onDayContaining: now, calendar: calendar)
+        guard let snapshot = snapshots.snapshot(for: ruleID), snapshot.isEnabled,
+              snapshot.kind == .timeLimit,
+              !snapshot.isPaused(at: now),
+              snapshot.isScheduledToday(at: now, calendar: calendar)
+        else { return }
+        let usage = ledger.usage(for: ruleID, onDayContaining: now, calendar: calendar)
+        if snapshot.limitReached(given: usage) {
+            shield(snapshot)
+        }
+    }
+
+    /// The wall-clock session granted by an "Open" press ended; the shield
+    /// returns so the next open costs another press.
+    func handleOpenSessionEnded(
+        ruleID: UUID, now: Date = .now, calendar: Calendar = .current
+    ) {
+        guard let snapshot = snapshots.snapshot(for: ruleID), snapshot.isEnabled,
+              snapshot.kind == .openLimit,
+              !snapshot.isPaused(at: now),
+              snapshot.isScheduledToday(at: now, calendar: calendar)
+        else { return }
+        shield(snapshot)
+    }
+
+    /// "Open" pressed on the shield. Spends one open and lifts the rule's
+    /// shield when the budget allows; returns whether a session was granted.
+    @discardableResult
+    func handleOpenRequest(
+        ruleID: UUID, now: Date = .now, calendar: Calendar = .current
+    ) -> Bool {
+        guard let snapshot = snapshots.snapshot(for: ruleID), snapshot.isEnabled,
+              snapshot.kind == .openLimit,
+              !snapshot.isPaused(at: now)
+        else { return false }
+        let usage = ledger.usage(for: ruleID, onDayContaining: now, calendar: calendar)
+        guard !snapshot.limitReached(given: usage) else { return false }
+        ledger.recordOpen(for: ruleID, onDayContaining: now, calendar: calendar)
+        shields.clearShield(ruleID: ruleID)
+        return true
+    }
+
+    private func shield(_ snapshot: RuleSnapshot) {
+        shields.applyShield(
+            ruleID: snapshot.id,
+            selectionData: snapshot.selectionData,
+            mode: .block,
+            blockAdultContent: snapshot.blockAdultContent
+        )
+    }
+}

Shared/MonitoringPlan.swift

@@ -0,0 +1,61 @@
+//
+//  MonitoringPlan.swift
+//  OpenAppLock
+//
+
+import Foundation
+
+/// Naming conventions and event layouts shared by the app (which starts
+/// DeviceActivity monitoring) and the monitor extension (which decodes what
+/// fired).
+enum MonitoringPlan {
+    private static let dailyPrefix = "rule-"
+    private static let sessionPrefix = "open-session-"
+    private static let minutePrefix = "minutes-"
+
+    /// Wall-clock length of one granted open. 15 minutes is DeviceActivity's
+    /// minimum schedule interval, so an "open" lasts at most this long before
+    /// the shield returns.
+    static let openSessionMinutes = 15
+
+    /// The always-on, midnight-to-midnight activity tracking a rule's day.
+    static func dailyActivityName(for ruleID: UUID) -> String {
+        dailyPrefix + ruleID.uuidString
+    }
+
+    /// The one-shot activity timing a granted open.
+    static func sessionActivityName(for ruleID: UUID) -> String {
+        sessionPrefix + ruleID.uuidString
+    }
+
+    static func ruleID(fromDailyActivityName name: String) -> UUID? {
+        guard name.hasPrefix(dailyPrefix) else { return nil }
+        return UUID(uuidString: String(name.dropFirst(dailyPrefix.count)))
+    }
+
+    static func ruleID(fromSessionActivityName name: String) -> UUID? {
+        guard name.hasPrefix(sessionPrefix) else { return nil }
+        return UUID(uuidString: String(name.dropFirst(sessionPrefix.count)))
+    }
+
+    static func minuteEventName(for minutes: Int) -> String {
+        minutePrefix + String(minutes)
+    }
+
+    static func minutes(fromEventName name: String) -> Int? {
+        guard name.hasPrefix(minutePrefix) else { return nil }
+        return Int(name.dropFirst(minutePrefix.count))
+    }
+
+    /// Cumulative-usage checkpoints for a time-limit rule: one event per
+    /// minute up to the budget so remaining time can be displayed live; the
+    /// final one doubles as the block trigger. (Budgets cap at 240 minutes,
+    /// comfortably inside DeviceActivity's event capacity.)
+    static func minuteEvents(forLimit limitMinutes: Int) -> [String: Int] {
+        Dictionary(
+            uniqueKeysWithValues: (1...max(1, limitMinutes)).map {
+                (minuteEventName(for: $0), $0)
+            }
+        )
+    }
+}

Shared/RuleKind.swift

@@ -0,0 +1,64 @@
+//
+//  RuleKind.swift
+//  OpenAppLock
+//
+
+import Foundation
+
+/// The three kinds of blocking rules, mirroring the reference app's "New Rule" sheet.
+enum RuleKind: String, Codable, CaseIterable, Sendable {
+    /// Block selected apps during a recurring time window.
+    case schedule
+    /// Block selected apps after a daily usage budget is spent.
+    case timeLimit
+    /// Block selected apps after a number of opens per day.
+    case openLimit
+
+    var displayName: String {
+        switch self {
+        case .schedule: "Schedule"
+        case .timeLimit: "Time Limit"
+        case .openLimit: "Open Limit"
+        }
+    }
+
+    var exampleText: String {
+        switch self {
+        case .schedule: "e.g. 9-5, Daily"
+        case .timeLimit: "e.g. 45m/day"
+        case .openLimit: "e.g. 5 opens/day"
+        }
+    }
+
+    var symbolName: String {
+        switch self {
+        case .schedule: "calendar"
+        case .timeLimit: "hourglass"
+        case .openLimit: "lock.fill"
+        }
+    }
+
+    /// Default name given to a brand-new rule of this kind (Opal: "In the Zone", "Time Keeper").
+    var defaultRuleName: String {
+        switch self {
+        case .schedule: "In the Zone"
+        case .timeLimit: "Time Keeper"
+        case .openLimit: "Gate Keeper"
+        }
+    }
+}
+
+/// How the rule's app selection is interpreted.
+enum SelectionMode: String, Codable, CaseIterable, Sendable {
+    /// Block the selected apps; everything else stays available.
+    case block
+    /// Block everything except the selected apps.
+    case allowOnly
+
+    var displayName: String {
+        switch self {
+        case .block: "Block"
+        case .allowOnly: "Allow Only"
+        }
+    }
+}

Shared/RuleSchedule.swift

@@ -0,0 +1,89 @@
+//
+//  RuleSchedule.swift
+//  OpenAppLock
+//
+
+import Foundation
+
+/// The recurring time window of a rule, independent of any persistence.
+///
+/// A window whose end is at or before its start crosses midnight: 22:00 → 06:00
+/// starts on an enabled day and ends the following morning. `start == end`
+/// means a full 24-hour window.
+struct RuleSchedule: Hashable, Sendable {
+    var startMinutes: Int
+    var endMinutes: Int
+    var days: Set<Weekday>
+
+    var crossesMidnight: Bool { endMinutes <= startMinutes }
+
+    var durationMinutes: Int {
+        crossesMidnight
+            ? RuleSchedule.minutesPerDay - startMinutes + endMinutes
+            : endMinutes - startMinutes
+    }
+
+    /// The window containing `date`, if the schedule is active at that moment.
+    ///
+    /// Checks today's window and, for midnight-crossing schedules, the window
+    /// that started yesterday. The day a window *starts* on is the day that
+    /// must be enabled.
+    func activeWindow(containing date: Date, calendar: Calendar = .current) -> DateInterval? {
+        for dayOffset in [0, -1] {
+            guard
+                let day = calendar.date(byAdding: .day, value: dayOffset, to: date),
+                let window = window(onDayContaining: day, calendar: calendar),
+                window.start <= date, date < window.end
+            else { continue }
+            return window
+        }
+        return nil
+    }
+
+    func isActive(at date: Date, calendar: Calendar = .current) -> Bool {
+        activeWindow(containing: date, calendar: calendar) != nil
+    }
+
+    /// The next moment the schedule will begin a window strictly after `date`.
+    func nextStart(after date: Date, calendar: Calendar = .current) -> Date? {
+        guard !days.isEmpty else { return nil }
+        for dayOffset in 0...7 {
+            guard
+                let day = calendar.date(byAdding: .day, value: dayOffset, to: date),
+                let window = window(onDayContaining: day, calendar: calendar),
+                window.start > date
+            else { continue }
+            return window.start
+        }
+        return nil
+    }
+
+    /// The window starting on the given day, or nil when that weekday is not enabled.
+    private func window(onDayContaining day: Date, calendar: Calendar) -> DateInterval? {
+        let dayStart = calendar.startOfDay(for: day)
+        guard
+            let weekday = Weekday(rawValue: calendar.component(.weekday, from: dayStart)),
+            days.contains(weekday),
+            let start = calendar.date(byAdding: .minute, value: startMinutes, to: dayStart),
+            let end = calendar.date(
+                byAdding: .minute, value: startMinutes + durationMinutes, to: dayStart
+            )
+        else { return nil }
+        return DateInterval(start: start, end: end)
+    }
+
+    private static let minutesPerDay = 24 * 60
+}
+
+extension RuleSchedule {
+    /// "09:00" style label for a minutes-from-midnight value, matching the reference UI.
+    static func timeLabel(forMinutes minutes: Int) -> String {
+        let clamped = ((minutes % (24 * 60)) + 24 * 60) % (24 * 60)
+        return String(format: "%02d:%02d", clamped / 60, clamped % 60)
+    }
+
+    /// "09:00 – 17:00" range label used by rule details and preset cards.
+    var timeRangeLabel: String {
+        "\(Self.timeLabel(forMinutes: startMinutes)) – \(Self.timeLabel(forMinutes: endMinutes))"
+    }
+}

Shared/RuleSnapshot.swift

@@ -0,0 +1,75 @@
+//
+//  RuleSnapshot.swift
+//  OpenAppLock
+//
+
+import Foundation
+
+/// Codable mirror of a rule, written to the app group by the app whenever
+/// rules change so the Screen Time extensions (which cannot open the
+/// SwiftData store) know what to enforce.
+struct RuleSnapshot: Codable, Equatable {
+    var id: UUID
+    var name: String
+    var kindRaw: String
+    var isEnabled: Bool
+    var hardMode: Bool
+    var blockAdultContent: Bool
+    var selectionModeRaw: String
+    var selectionData: Data?
+    var dayNumbers: [Int]
+    var dailyLimitMinutes: Int
+    var maxOpens: Int
+    var pausedUntil: Date?
+
+    var kind: RuleKind { RuleKind(rawValue: kindRaw) ?? .schedule }
+    var days: Set<Weekday> { Set(dayNumbers.compactMap(Weekday.init(rawValue:))) }
+
+    func isScheduledToday(at now: Date, calendar: Calendar = .current) -> Bool {
+        guard let weekday = Weekday(rawValue: calendar.component(.weekday, from: now)) else {
+            return false
+        }
+        return days.contains(weekday)
+    }
+
+    /// Whether the given usage exhausts this rule's daily budget.
+    func limitReached(given usage: RuleUsage) -> Bool {
+        switch kind {
+        case .schedule: false
+        case .timeLimit: usage.minutesUsed >= dailyLimitMinutes
+        case .openLimit: usage.opensUsed >= maxOpens
+        }
+    }
+
+    /// Whether the user unblocked this rule for the rest of the day.
+    func isPaused(at now: Date) -> Bool {
+        guard let pausedUntil else { return false }
+        return pausedUntil > now
+    }
+}
+
+/// Persistence for the rule mirror in the shared app-group defaults.
+final class RuleSnapshotStore {
+    private static let key = "ruleSnapshots"
+    private let defaults: UserDefaults
+
+    init(defaults: UserDefaults = AppGroup.defaults) {
+        self.defaults = defaults
+    }
+
+    func save(_ snapshots: [RuleSnapshot]) {
+        guard let data = try? JSONEncoder().encode(snapshots) else { return }
+        defaults.set(data, forKey: Self.key)
+    }
+
+    func load() -> [RuleSnapshot] {
+        guard let data = defaults.data(forKey: Self.key),
+              let snapshots = try? JSONDecoder().decode([RuleSnapshot].self, from: data)
+        else { return [] }
+        return snapshots
+    }
+
+    func snapshot(for ruleID: UUID) -> RuleSnapshot? {
+        load().first { $0.id == ruleID }
+    }
+}

Shared/ShieldController.swift

@@ -0,0 +1,139 @@
+//
+//  ShieldController.swift
+//  OpenAppLock
+//
+
+import FamilyControls
+import Foundation
+import ManagedSettings
+
+/// Applies and clears app shields for rules. One implementation talks to
+/// ManagedSettings; the mock records calls for tests.
+protocol ShieldApplying: AnyObject {
+    func applyShield(
+        ruleID: UUID, selectionData: Data?, mode: SelectionMode, blockAdultContent: Bool
+    )
+    /// Clears the shield of a single rule (used by the extensions for day
+    /// resets and granted opens).
+    func clearShield(ruleID: UUID)
+    /// Clears every shield except those for the given rule IDs. Covers rules
+    /// that were deleted or expired while the app was not running.
+    func clearShields(except activeRuleIDs: Set<UUID>)
+}
+
+/// Real shield enforcement via per-rule `ManagedSettingsStore`s. Store names
+/// are tracked in the shared app-group defaults (ManagedSettings cannot
+/// enumerate stores) so the app and extensions see one consistent set.
+final class ManagedSettingsShieldController: ShieldApplying {
+    private static let trackedIDsKey = "shieldedRuleIDs"
+    private let defaults: UserDefaults
+
+    init(defaults: UserDefaults = AppGroup.defaults) {
+        self.defaults = defaults
+    }
+
+    func applyShield(
+        ruleID: UUID, selectionData: Data?, mode: SelectionMode, blockAdultContent: Bool
+    ) {
+        let store = store(for: ruleID)
+        let selection = AppSelectionCodec.decode(selectionData)
+        switch mode {
+        case .block:
+            store.shield.applications =
+                selection.applicationTokens.isEmpty ? nil : selection.applicationTokens
+            store.shield.applicationCategories =
+                selection.categoryTokens.isEmpty ? nil : .specific(selection.categoryTokens)
+            store.shield.webDomains =
+                selection.webDomainTokens.isEmpty ? nil : selection.webDomainTokens
+        case .allowOnly:
+            store.shield.applicationCategories = .all(except: selection.applicationTokens)
+            store.shield.webDomainCategories = .all(except: selection.webDomainTokens)
+        }
+        // Screen Time's "Limit Adult Websites" filter for the rule's lifetime.
+        store.webContent.blockedByFilter = blockAdultContent ? .auto() : nil
+        track(ruleID: ruleID)
+    }
+
+    func clearShield(ruleID: UUID) {
+        store(for: ruleID).clearAllSettings()
+        untrack(ruleID: ruleID)
+    }
+
+    func clearShields(except activeRuleIDs: Set<UUID>) {
+        for ruleID in trackedIDs.subtracting(activeRuleIDs) {
+            clearShield(ruleID: ruleID)
+        }
+    }
+
+    private func store(for ruleID: UUID) -> ManagedSettingsStore {
+        ManagedSettingsStore(named: ManagedSettingsStore.Name("rule-\(ruleID.uuidString)"))
+    }
+
+    private var trackedIDs: Set<UUID> {
+        Set((defaults.stringArray(forKey: Self.trackedIDsKey) ?? []).compactMap(UUID.init))
+    }
+
+    private func track(ruleID: UUID) {
+        let ids = trackedIDs.union([ruleID])
+        defaults.set(ids.map(\.uuidString).sorted(), forKey: Self.trackedIDsKey)
+    }
+
+    private func untrack(ruleID: UUID) {
+        let ids = trackedIDs.subtracting([ruleID])
+        defaults.set(ids.map(\.uuidString).sorted(), forKey: Self.trackedIDsKey)
+    }
+}
+
+/// Records shield operations without touching the system. Used by tests and
+/// UI-test launches.
+final class MockShieldController: ShieldApplying {
+    private(set) var shieldedRuleIDs: Set<UUID> = []
+    private(set) var appliedModes: [UUID: SelectionMode] = [:]
+    private(set) var appliedAdultContentFlags: [UUID: Bool] = [:]
+    private(set) var appliedSelectionData: [UUID: Data?] = [:]
+
+    func applyShield(
+        ruleID: UUID, selectionData: Data?, mode: SelectionMode, blockAdultContent: Bool
+    ) {
+        shieldedRuleIDs.insert(ruleID)
+        appliedModes[ruleID] = mode
+        appliedAdultContentFlags[ruleID] = blockAdultContent
+        appliedSelectionData[ruleID] = selectionData
+    }
+
+    func clearShield(ruleID: UUID) {
+        shieldedRuleIDs.remove(ruleID)
+        appliedModes[ruleID] = nil
+        appliedAdultContentFlags[ruleID] = nil
+        appliedSelectionData[ruleID] = nil
+    }
+
+    func clearShields(except activeRuleIDs: Set<UUID>) {
+        shieldedRuleIDs.formIntersection(activeRuleIDs)
+        appliedModes = appliedModes.filter { activeRuleIDs.contains($0.key) }
+        appliedAdultContentFlags = appliedAdultContentFlags.filter {
+            activeRuleIDs.contains($0.key)
+        }
+        appliedSelectionData = appliedSelectionData.filter { activeRuleIDs.contains($0.key) }
+    }
+}
+
+/// Encodes/decodes `FamilyActivitySelection` for persistence on the rule model.
+enum AppSelectionCodec {
+    static func encode(_ selection: FamilyActivitySelection) -> Data? {
+        try? JSONEncoder().encode(selection)
+    }
+
+    static func decode(_ data: Data?) -> FamilyActivitySelection {
+        guard let data,
+              let selection = try? JSONDecoder().decode(FamilyActivitySelection.self, from: data)
+        else { return FamilyActivitySelection() }
+        return selection
+    }
+
+    static func count(of selection: FamilyActivitySelection) -> Int {
+        selection.applicationTokens.count
+            + selection.categoryTokens.count
+            + selection.webDomainTokens.count
+    }
+}

Shared/ShieldLookup.swift

@@ -0,0 +1,44 @@
+//
+//  ShieldLookup.swift
+//  OpenAppLock
+//
+
+import FamilyControls
+import Foundation
+import ManagedSettings
+
+/// Matches shielded tokens back to the rule that shields them, so the shield
+/// UI can offer "Open" with the right counts for open-limit rules.
+enum ShieldLookup {
+    static func openLimitSnapshot(
+        containingApplication token: ApplicationToken, in snapshots: [RuleSnapshot]
+    ) -> RuleSnapshot? {
+        snapshots.first { snapshot in
+            guard snapshot.kind == .openLimit, snapshot.isEnabled else { return false }
+            return AppSelectionCodec.decode(snapshot.selectionData)
+                .applicationTokens.contains(token)
+        }
+    }
+
+    static func openLimitSnapshot(
+        containingCategory token: ActivityCategoryToken, in snapshots: [RuleSnapshot]
+    ) -> RuleSnapshot? {
+        snapshots.first { snapshot in
+            guard snapshot.kind == .openLimit, snapshot.isEnabled else { return false }
+            return AppSelectionCodec.decode(snapshot.selectionData)
+                .categoryTokens.contains(token)
+        }
+    }
+
+    /// Any enabled rule whose selection includes the application (for naming
+    /// plain blocked shields).
+    static func snapshot(
+        containingApplication token: ApplicationToken, in snapshots: [RuleSnapshot]
+    ) -> RuleSnapshot? {
+        snapshots.first { snapshot in
+            guard snapshot.isEnabled else { return false }
+            return AppSelectionCodec.decode(snapshot.selectionData)
+                .applicationTokens.contains(token)
+        }
+    }
+}

Shared/UsageLedger.swift

@@ -0,0 +1,93 @@
+//
+//  UsageLedger.swift
+//  OpenAppLock
+//
+
+import Foundation
+
+/// What a limit rule has consumed on a given day. Written by the
+/// DeviceActivity monitor (minutes) and shield-action extension (opens);
+/// read by the app for display and enforcement.
+struct RuleUsage: Codable, Equatable {
+    var minutesUsed = 0
+    var opensUsed = 0
+}
+
+/// Read access to per-rule, per-day usage.
+protocol UsageReading: AnyObject {
+    func usage(for ruleID: UUID, onDayContaining date: Date, calendar: Calendar) -> RuleUsage
+}
+
+extension UsageReading {
+    func usage(for ruleID: UUID, onDayContaining date: Date) -> RuleUsage {
+        usage(for: ruleID, onDayContaining: date, calendar: .current)
+    }
+}
+
+/// Usage bookkeeping in the shared app-group defaults, keyed by calendar day
+/// and rule. Old days are simply ignored; midnight needs no reset step.
+final class UsageLedger: UsageReading {
+    private let defaults: UserDefaults
+
+    init(defaults: UserDefaults = AppGroup.defaults) {
+        self.defaults = defaults
+    }
+
+    /// "2026-06-12" — calendar-date key so budgets roll over at midnight.
+    static func dayKey(for date: Date, calendar: Calendar = .current) -> String {
+        let parts = calendar.dateComponents([.year, .month, .day], from: date)
+        return String(format: "%04d-%02d-%02d", parts.year ?? 0, parts.month ?? 0, parts.day ?? 0)
+    }
+
+    func usage(
+        for ruleID: UUID, onDayContaining date: Date, calendar: Calendar = .current
+    ) -> RuleUsage {
+        guard let data = defaults.data(forKey: key(ruleID, date, calendar)),
+              let usage = try? JSONDecoder().decode(RuleUsage.self, from: data)
+        else { return RuleUsage() }
+        return usage
+    }
+
+    func setUsage(
+        _ usage: RuleUsage, for ruleID: UUID, onDayContaining date: Date,
+        calendar: Calendar = .current
+    ) {
+        guard let data = try? JSONEncoder().encode(usage) else { return }
+        defaults.set(data, forKey: key(ruleID, date, calendar))
+    }
+
+    /// Threshold events report cumulative totals, so minutes only move up.
+    func recordMinutesUsed(
+        _ minutes: Int, for ruleID: UUID, onDayContaining date: Date,
+        calendar: Calendar = .current
+    ) {
+        var usage = self.usage(for: ruleID, onDayContaining: date, calendar: calendar)
+        usage.minutesUsed = max(usage.minutesUsed, minutes)
+        setUsage(usage, for: ruleID, onDayContaining: date, calendar: calendar)
+    }
+
+    @discardableResult
+    func recordOpen(
+        for ruleID: UUID, onDayContaining date: Date, calendar: Calendar = .current
+    ) -> RuleUsage {
+        var usage = self.usage(for: ruleID, onDayContaining: date, calendar: calendar)
+        usage.opensUsed += 1
+        setUsage(usage, for: ruleID, onDayContaining: date, calendar: calendar)
+        return usage
+    }
+
+    private func key(_ ruleID: UUID, _ date: Date, _ calendar: Calendar) -> String {
+        "usage/\(Self.dayKey(for: date, calendar: calendar))/\(ruleID.uuidString)"
+    }
+}
+
+/// Seedable in-memory usage for tests and UI-test scenarios.
+final class MockUsageLedger: UsageReading {
+    var usageByRule: [UUID: RuleUsage] = [:]
+
+    func usage(
+        for ruleID: UUID, onDayContaining date: Date, calendar: Calendar
+    ) -> RuleUsage {
+        usageByRule[ruleID] ?? RuleUsage()
+    }
+}

Shared/Weekday.swift

@@ -0,0 +1,65 @@
+//
+//  Weekday.swift
+//  OpenAppLock
+//
+
+import Foundation
+
+/// A day of the week, using `Calendar` weekday numbering (1 = Sunday … 7 = Saturday).
+enum Weekday: Int, CaseIterable, Codable, Hashable, Sendable {
+    case sunday = 1
+    case monday = 2
+    case tuesday = 3
+    case wednesday = 4
+    case thursday = 5
+    case friday = 6
+    case saturday = 7
+
+    static let weekdays: Set<Weekday> = [.monday, .tuesday, .wednesday, .thursday, .friday]
+    static let weekends: Set<Weekday> = [.saturday, .sunday]
+    static let everyDay: Set<Weekday> = Set(Weekday.allCases)
+
+    /// Display order used by the day picker, matching the reference UI: S M T W T F S.
+    static let displayOrder: [Weekday] = [
+        .sunday, .monday, .tuesday, .wednesday, .thursday, .friday, .saturday,
+    ]
+
+    /// Single-letter label for the circular day toggles.
+    var shortLabel: String {
+        switch self {
+        case .sunday, .saturday: "S"
+        case .monday: "M"
+        case .tuesday, .thursday: "T"
+        case .wednesday: "W"
+        case .friday: "F"
+        }
+    }
+
+    /// Three-letter abbreviation used in custom day summaries ("Mon, Wed, Fri").
+    var abbreviation: String {
+        switch self {
+        case .sunday: "Sun"
+        case .monday: "Mon"
+        case .tuesday: "Tue"
+        case .wednesday: "Wed"
+        case .thursday: "Thu"
+        case .friday: "Fri"
+        case .saturday: "Sat"
+        }
+    }
+}
+
+extension Set<Weekday> {
+    /// Human-readable summary shown next to the day picker and in rule details:
+    /// "Weekdays", "Weekends", "Every day", "Never", or a list like "Mon, Wed, Fri".
+    var summary: String {
+        if self == Weekday.everyDay { return "Every day" }
+        if self == Weekday.weekdays { return "Weekdays" }
+        if self == Weekday.weekends { return "Weekends" }
+        if isEmpty { return "Never" }
+        return Weekday.displayOrder
+            .filter(contains)
+            .map(\.abbreviation)
+            .joined(separator: ", ")
+    }
+}