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>

OpenAppLock.xcodeproj/xcshareddata/xcschemes/OpenAppLock.xcscheme

@@ -0,0 +1,99 @@
+<?xml version="1.0" encoding="UTF-8"?>
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+   LastUpgradeVersion = "2600"
+   version = "1.7">
+   <BuildAction
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+      buildImplicitDependencies = "YES">
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+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
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+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "20A7EDCD2E47B7CD0097608D"
+               BuildableName = "OpenAppLock.app"
+               BlueprintName = "OpenAppLock"
+               ReferencedContainer = "container:OpenAppLock.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
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+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
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+      shouldAutocreateTestPlan = "YES">
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+               BuildableName = "OpenAppLockTests.xctest"
+               BlueprintName = "OpenAppLockTests"
+               ReferencedContainer = "container:OpenAppLock.xcodeproj">
+            </BuildableReference>
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+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "20A7EDE62E47B7CF0097608D"
+               BuildableName = "OpenAppLockUITests.xctest"
+               BlueprintName = "OpenAppLockUITests"
+               ReferencedContainer = "container:OpenAppLock.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
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+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
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+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
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+            BlueprintIdentifier = "20A7EDCD2E47B7CD0097608D"
+            BuildableName = "OpenAppLock.app"
+            BlueprintName = "OpenAppLock"
+            ReferencedContainer = "container:OpenAppLock.xcodeproj">
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+            ReferencedContainer = "container:OpenAppLock.xcodeproj">
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+      revealArchiveInOrganizer = "YES">
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