feat: re-skin to native three-tab UI and add Uninstall Protection

Replace the custom themed presentation with the bare native iOS design
language across a three-tab TabView (Home / Rules / Settings):

- MainTabView hosts the enforcement lifecycle (refresh loop, rule-change
  and scene-active reconcile) so it runs regardless of the selected tab
- HomeView: "Currently Blocking" + "Usage" sections (replaces AppsHomeView)
- RulesListView: rules grouped into Schedule / Time Limit / Open Limit
- SettingsView: Uninstall Protection toggle + Manage App Lists
- AppListLibraryView / ManageAppListsView: shared App List management
- AppSettings: app-group-backed settings store

Uninstall Protection: while enabled and any Hard Mode rule is actively
blocking, deny device app-removal via a dedicated ManagedSettingsStore
(RulePolicy.shouldDenyAppRemoval -> RuleEnforcer -> ShieldController).

Slim AppListPickerSheet to the picker role; drop AppsHomeView and the
custom Theme/HoldToCommitButton/RuleCardView chrome. Update spec section 6
and the unit/UI test suites accordingly.

OpenAppLockUITests/SettingsUITests.swift

@@ -0,0 +1,67 @@
+//
+//  SettingsUITests.swift
+//  OpenAppLockUITests
+//
+
+import XCTest
+
+/// The Settings tab: the Uninstall Protection toggle and the Manage App Lists
+/// flow (which reuses the rule editor's app-list library, minus selection).
+final class SettingsUITests: XCTestCase {
+    override func setUpWithError() throws {
+        continueAfterFailure = false
+    }
+
+    func testUninstallProtectionToggleStartsOffAndFlips() throws {
+        let app = XCUIApplication.launchOpenAppLock()
+        app.goToSettingsTab()
+
+        let toggle = app.switches["uninstallProtectionToggle"].waitToAppear()
+        XCTAssertEqual(toggle.value as? String, "0", "Uninstall Protection should default off")
+        // `.tap()` lands on the element's center (over the label) and doesn't
+        // reliably flip a SwiftUI switch — tap the control itself.
+        toggle.coordinate(withNormalizedOffset: CGVector(dx: 0.92, dy: 0.5)).tap()
+        XCTAssertEqual(toggle.value as? String, "1", "Tapping should turn it on")
+    }
+
+    func testManageAppListsCreateFlow() throws {
+        let app = XCUIApplication.launchOpenAppLock()
+        app.goToSettingsTab()
+
+        app.element("manageAppListsButton").waitToAppear().tap()
+
+        // Fresh install: no lists yet — the same create flow as the rule editor.
+        app.element("emptyAppListsLabel").waitToAppear()
+        app.buttons["newAppListButton"].tap()
+
+        let nameField = app.textFields["appListNameField"].waitToAppear()
+        nameField.tap()
+        nameField.typeText("Distractions\n")
+
+        app.element("emptySelectionLabel").waitToAppear()
+        app.buttons["editAppsButton"].tap()
+        app.element("selectionCountLabel").waitToAppear()
+        app.buttons["confirmSelectionButton"].tap()
+
+        app.buttons["saveAppListButton"].waitToAppear().tap()
+
+        // Saving returns to the management list with the new list present.
+        app.element("appListRow-Distractions").waitToAppear()
+    }
+
+    func testManageAppListsLockedDuringHardSession() throws {
+        let app = XCUIApplication.launchOpenAppLock(seedScenario: "hard-mode-active")
+        app.goToSettingsTab()
+
+        app.element("manageAppListsButton").waitToAppear().tap()
+
+        // The seeded "Distractions" list is visible but read-only while the
+        // hard-mode rule is blocking — same lock as the rule editor's picker.
+        app.element("appListRow-Distractions").waitToAppear()
+        app.element("appListsLockedNotice").waitToAppear()
+        XCTAssertFalse(
+            app.buttons["editAppListButton-Distractions"].exists,
+            "App lists must be read-only while a Hard Mode rule is blocking"
+        )
+    }
+}