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/UITestSupport.swift

@@ -32,6 +32,16 @@ extension XCUIApplication {
     }
 }
 
+extension XCUIApplication {
+    /// Switches to the Home tab (Currently Blocking + Usage). Home is the
+    /// default selection, so most Home-tab tests don't need to call this.
+    func goToHomeTab() { tabBars.buttons["Home"].waitToAppear().tap() }
+    /// Switches to the Rules tab (the rule list + New Rule button).
+    func goToRulesTab() { tabBars.buttons["Rules"].waitToAppear().tap() }
+    /// Switches to the Settings tab (Uninstall Protection + Manage App Lists).
+    func goToSettingsTab() { tabBars.buttons["Settings"].waitToAppear().tap() }
+}
+
 extension XCUIElement {
     /// Asserts the element appears within the timeout, then returns it.
     @discardableResult