feat: add XCUITest suite with 10 critical flow tests and QA test plan

Add comprehensive UI test infrastructure with Page Object pattern,
accessibility identifiers, UI test mode (--ui-testing, --reset-state,
--disable-animations), and 10 passing tests covering app launch, tab
navigation, trip wizard, trip saving, settings, schedule, and
accessibility at XXXL Dynamic Type. Also adds a 229-case QA test plan
Excel workbook for manual QA handoff.

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

SportsTimeUITests/Tests/TabNavigationTests.swift

@@ -0,0 +1,47 @@
+//
+//  TabNavigationTests.swift
+//  SportsTimeUITests
+//
+//  Verifies navigation through all 5 tabs.
+//
+
+import XCTest
+
+final class TabNavigationTests: BaseUITestCase {
+
+    /// Navigates through all 5 tabs and asserts each one loads.
+    @MainActor
+    func testTabNavigationCycle() {
+        let home = HomeScreen(app: app)
+        home.waitForLoad()
+
+        // Schedule tab
+        home.switchToTab(home.scheduleTab)
+        let schedule = ScheduleScreen(app: app)
+        schedule.assertLoaded()
+
+        // My Trips tab
+        home.switchToTab(home.myTripsTab)
+        let myTrips = MyTripsScreen(app: app)
+        myTrips.assertEmpty()
+
+        // Progress tab (Pro-gated, but UI test mode forces Pro)
+        home.switchToTab(home.progressTab)
+        // Just verify the tab switched without crash
+        let progressNav = app.navigationBars.firstMatch
+        XCTAssertTrue(progressNav.waitForExistence(timeout: BaseUITestCase.defaultTimeout),
+                       "Progress tab should load")
+
+        // Settings tab
+        home.switchToTab(home.settingsTab)
+        let settings = SettingsScreen(app: app)
+        settings.assertLoaded()
+
+        // Return home
+        home.switchToTab(home.homeTab)
+        XCTAssertTrue(home.startPlanningButton.waitForExistence(timeout: BaseUITestCase.shortTimeout),
+                       "Should return to Home tab")
+
+        captureScreenshot(named: "TabNavigation-ReturnHome")
+    }
+}