Rewrite all UI tests following fail-fast TEST_RULES patterns

Rewrote 60+ test files to follow honeydue-style test guidelines:
- defaultTimeout=2s, navigationTimeout=5s — fail fast, no long waits
- No coordinate taps (except onboarding paged TabView swipes)
- No sleep(), no retry loops
- No guard...else { return } silent passes — XCTFail everywhere
- All elements by accessibility ID via UITestID constants
- Screen objects for all navigation/actions/assertions
- One logical assertion per test method

Added missing accessibility identifiers to app views:
- MonthView.swift: added AccessibilityID.MonthView.grid to ScrollView
- YearView.swift: added AccessibilityID.YearView.heatmap to ScrollView

Framework rewrites:
- BaseUITestCase: added session ID, localeArguments, extraLaunchArguments
- WaitHelpers: waitForExistenceOrFail, waitUntilHittableOrFail,
  waitForNonExistence, scrollIntoView, forceTap
- All 7 screen objects rewritten with fail-fast semantics
- TEST_RULES.md added with non-negotiable rules

Known remaining issues:
- OnboardingTests: paged TabView swipes unreliable on iOS 26 simulator
- SettingsLegalLinksTests: EULA/Privacy buttons too deep in DEBUG scroll
- Customization horizontal picker scrolling needs further tuning

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Tests iOS/TrialExpirationTests.swift

@@ -12,23 +12,27 @@ final class TrialExpirationTests: BaseUITestCase {
     override var bypassSubscription: Bool { false }
     override var expireTrial: Bool { true }
 
-    /// TC-078: When trial is expired, Settings shows "Trial expired" text
-    /// and the upgrade banner is visible.
+    /// TC-078: When trial is expired, Settings shows upgrade banner.
     func testTrialExpired_ShowsExpiredBanner() {
-        let tabBar = TabBarScreen(app: app)
-        let settingsScreen = tabBar.tapSettings()
+        let settingsScreen = TabBarScreen(app: app).tapSettings()
         settingsScreen.assertVisible()
 
-        // Verify upgrade banner is visible (trial expired, not subscribed)
         settingsScreen.assertUpgradeBannerVisible()
 
-        // Check for "Trial expired" text in the banner
-        let expiredText = app.staticTexts["Trial expired"]
-        XCTAssertTrue(
-            expiredText.waitForExistence(timeout: 5),
-            "Settings should show 'Trial expired' text when trial has expired"
-        )
-
         captureScreenshot(name: "trial_expired_banner")
     }
+
+    /// TC-078: When trial is expired, "Trial expired" text is shown.
+    func testTrialExpired_ShowsExpiredText() {
+        let settingsScreen = TabBarScreen(app: app).tapSettings()
+        settingsScreen.assertVisible()
+
+        let expiredText = app.staticTexts["Trial expired"]
+        expiredText.waitForExistenceOrFail(
+            timeout: navigationTimeout,
+            message: "Settings should show 'Trial expired' text when trial has expired"
+        )
+
+        captureScreenshot(name: "trial_expired_text")
+    }
 }