Complete re-validation remediation: KMP architecture, iOS platform, XCUITest rewrite

Phases 1-6 of fixes.md — closes all 13 issues from codex_issues_2.md re-validation:

KMP Architecture:
- Fix subscription purchase/restore response contract (VerificationResponse aligned)
- Add feature benefits auth token + APILayer init flow
- Remove ResidenceFormScreen direct API bypass (use APILayer)
- Wire paywall purchase/restore to real SubscriptionApi calls

iOS Platform:
- Add iOS Keychain token storage via Swift KeychainHelper
- Implement Google Sign-In via ASWebAuthenticationSession (GoogleSignInManager)
- DocumentViewModelWrapper observes DataManager for auto-updates
- Add missing accessibility identifiers (document, task columns, Google Sign-In)

XCUITest Rewrite:
- Rewrite test infrastructure: zero sleep() calls, accessibility ID lookups
- Create AuthCriticalPathTests and NavigationCriticalPathTests
- Delete 14 legacy brittle test files (Suite0-10, templates)
- Fix CaseraTests module import (@testable import Casera)

All platforms build clean. TEST BUILD SUCCEEDED.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

iosApp/CaseraUITests/CriticalPath/NavigationCriticalPathTests.swift

@@ -0,0 +1,169 @@
+import XCTest
+
+/// Critical path tests for core navigation.
+///
+/// Validates tab bar navigation, settings access, and screen transitions.
+/// Requires a logged-in user. Zero sleep() calls — all waits are condition-based.
+final class NavigationCriticalPathTests: XCTestCase {
+    var app: XCUIApplication!
+
+    override func setUp() {
+        super.setUp()
+        continueAfterFailure = false
+        app = TestLaunchConfig.launchApp()
+        ensureLoggedIn()
+    }
+
+    override func tearDown() {
+        app = nil
+        super.tearDown()
+    }
+
+    private func ensureLoggedIn() {
+        let login = LoginScreen(app: app)
+        if login.emailField.waitForExistence(timeout: 15) {
+            let user = TestFixtures.TestUser.existing
+            login.login(email: user.email, password: user.password)
+        }
+        let main = MainTabScreen(app: app)
+        _ = main.residencesTab.waitForExistence(timeout: 15)
+    }
+
+    // MARK: - Tab Navigation
+
+    func testAllTabsExist() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        XCTAssertTrue(main.residencesTab.exists, "Residences tab should exist")
+        XCTAssertTrue(main.tasksTab.exists, "Tasks tab should exist")
+        XCTAssertTrue(main.contractorsTab.exists, "Contractors tab should exist")
+        XCTAssertTrue(main.documentsTab.exists, "Documents tab should exist")
+    }
+
+    func testNavigateToTasksTab() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        main.goToTasks()
+        XCTAssertTrue(main.tasksTab.isSelected, "Tasks tab should be selected")
+    }
+
+    func testNavigateToContractorsTab() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        main.goToContractors()
+        XCTAssertTrue(main.contractorsTab.isSelected, "Contractors tab should be selected")
+    }
+
+    func testNavigateToDocumentsTab() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        main.goToDocuments()
+        XCTAssertTrue(main.documentsTab.isSelected, "Documents tab should be selected")
+    }
+
+    func testNavigateBackToResidencesTab() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        main.goToDocuments()
+        main.goToResidences()
+        XCTAssertTrue(main.residencesTab.isSelected, "Residences tab should be selected")
+    }
+
+    // MARK: - Settings Access
+
+    func testSettingsButtonExists() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        main.goToResidences()
+        XCTAssertTrue(
+            main.settingsButton.waitForExistence(timeout: 5),
+            "Settings button should exist on Residences screen"
+        )
+    }
+
+    // MARK: - Add Buttons
+
+    func testResidenceAddButtonExists() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        main.goToResidences()
+        let addButton = app.buttons[AccessibilityIdentifiers.Residence.addButton]
+        XCTAssertTrue(
+            addButton.waitForExistence(timeout: 5),
+            "Residence add button should exist"
+        )
+    }
+
+    func testTaskAddButtonExists() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        main.goToTasks()
+        let addButton = app.buttons[AccessibilityIdentifiers.Task.addButton]
+        XCTAssertTrue(
+            addButton.waitForExistence(timeout: 5),
+            "Task add button should exist"
+        )
+    }
+
+    func testContractorAddButtonExists() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        main.goToContractors()
+        let addButton = app.buttons[AccessibilityIdentifiers.Contractor.addButton]
+        XCTAssertTrue(
+            addButton.waitForExistence(timeout: 5),
+            "Contractor add button should exist"
+        )
+    }
+
+    func testDocumentAddButtonExists() {
+        let main = MainTabScreen(app: app)
+        guard main.residencesTab.waitForExistence(timeout: 10) else {
+            XCTFail("Main screen did not appear")
+            return
+        }
+
+        main.goToDocuments()
+        let addButton = app.buttons[AccessibilityIdentifiers.Document.addButton]
+        XCTAssertTrue(
+            addButton.waitForExistence(timeout: 5),
+            "Document add button should exist"
+        )
+    }
+}