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/OnboardingVotingTests.swift

@@ -2,7 +2,7 @@
 //  OnboardingVotingTests.swift
 //  Tests iOS
 //
-//  TC-122: Onboarding day voting — Today vs Yesterday selection.
+//  TC-122: Onboarding day voting -- Today vs Yesterday selection.
 //
 
 import XCTest
@@ -11,69 +11,32 @@ final class OnboardingVotingTests: BaseUITestCase {
     override var seedFixture: String? { "empty" }
     override var skipOnboarding: Bool { false }
 
-    /// TC-122: Tapping Today and Yesterday buttons toggles the selection.
+    /// TC-122: Tapping Yesterday and Today buttons toggles the selection.
     func testOnboarding_DayVoting_TodayAndYesterday() {
         let onboarding = OnboardingScreen(app: app)
+        onboarding.assertVisible()
 
-        // Wait for welcome screen
-        XCTAssertTrue(
-            onboarding.welcomeScreen.waitForExistence(timeout: 10),
-            "Onboarding welcome screen should appear"
-        )
+        // Swipe from Welcome to the Day page
+        onboarding.swipeToNext()
 
-        // Swipe once: Welcome → Day (Day is now page 2, before Time)
-        swipeToNext()
-
-        // Look for the "Which day should" title text to confirm we're on the day page
-        let dayTitle = app.staticTexts.matching(
-            NSPredicate(format: "label CONTAINS[c] 'Which day'")
-        ).firstMatch
-
-        XCTAssertTrue(
-            dayTitle.waitForExistence(timeout: 5),
-            "Day screen title 'Which day should you rate?' should be visible"
-        )
-
-        captureScreenshot(name: "onboarding_day_screen")
-
-        // Tap the Yesterday card by looking for its text
-        let yesterdayText = app.staticTexts["Yesterday, Rate the previous day"]
-        let todayText = app.staticTexts["Today, Rate the current day"]
-
-        // Fallback: try the button by accessibility identifier
+        // Tap Yesterday via accessibility ID
         let yesterdayButton = app.element(UITestID.Onboarding.dayYesterday)
-        let todayButton = app.element(UITestID.Onboarding.dayToday)
-
-        // Try tapping Yesterday via text label or accessibility ID
-        if yesterdayButton.exists {
-            yesterdayButton.coordinate(withNormalizedOffset: CGVector(dx: 0.5, dy: 0.5)).tap()
-        } else if yesterdayText.exists {
-            yesterdayText.tap()
-        } else {
-            // Fallback: tap coordinate at roughly the "Yesterday" card position
-            app.coordinate(withNormalizedOffset: CGVector(dx: 0.5, dy: 0.72)).tap()
-        }
+        yesterdayButton.waitUntilHittableOrFail(
+            timeout: navigationTimeout,
+            message: "Yesterday button should be hittable on the Day screen"
+        )
+        yesterdayButton.forceTap()
 
         captureScreenshot(name: "onboarding_day_yesterday_tapped")
 
-        // Tap Today
-        if todayButton.exists {
-            todayButton.coordinate(withNormalizedOffset: CGVector(dx: 0.5, dy: 0.5)).tap()
-        } else if todayText.exists {
-            todayText.tap()
-        } else {
-            app.coordinate(withNormalizedOffset: CGVector(dx: 0.5, dy: 0.60)).tap()
-        }
+        // Tap Today via accessibility ID
+        let todayButton = app.element(UITestID.Onboarding.dayToday)
+        todayButton.waitUntilHittableOrFail(
+            timeout: defaultTimeout,
+            message: "Today button should be hittable on the Day screen"
+        )
+        todayButton.forceTap()
 
         captureScreenshot(name: "onboarding_day_today_tapped")
     }
-
-    // MARK: - Private
-
-    private func swipeToNext() {
-        let start = app.coordinate(withNormalizedOffset: CGVector(dx: 0.9, dy: 0.18))
-        let end = app.coordinate(withNormalizedOffset: CGVector(dx: 0.1, dy: 0.18))
-        start.press(forDuration: 0.05, thenDragTo: end)
-        _ = app.waitForExistence(timeout: 1.0)
-    }
 }