test(ios): cover context erasure and native capability restrictions

Add Apple-platform tests without presenting them as Linux results. Improve native dark-mode contrast and keep the portable policy suite separate from WebKit tests. Swift formatting and syntax checks pass; Xcode execution remains required.

ios/Tests/BrowserModelTests.swift

@@ -0,0 +1,28 @@
+import WebKit
+import XCTest
+
+@testable import Yuvomi
+
+final class BrowserModelTests: XCTestCase {
+    @MainActor
+    func testMainViewHasNoNativeBridgeOrAutomaticPopupAccess() {
+        let model = BrowserModel()
+        XCTAssertFalse(model.web.configuration.preferences.javaScriptCanOpenWindowsAutomatically)
+        XCTAssertTrue(model.web.configuration.userContentController.userScripts.isEmpty)
+        XCTAssertTrue(model.web.configuration.websiteDataStore.isPersistent)
+        XCTAssertFalse(model.web.isInspectable)
+    }
+
+    @MainActor
+    func testServerErasureReplacesHistoryContext() async {
+        let model = BrowserModel()
+        let previousView = model.web
+        await withCheckedContinuation { continuation in
+            model.erase { continuation.resume() }
+        }
+        XCTAssertFalse(previousView === model.web)
+        XCTAssertNil(model.server)
+        XCTAssertFalse(model.canGoBack)
+        XCTAssertNil(model.error)
+    }
+}