Refactor ZStack layouts to .background(), add Year View accessibility IDs, triage QA test plan

Replace ZStack-with-gradient patterns with idiomatic .background() modifier
across onboarding, customize, and settings views. Add accessibility identifiers
to Year View charts for UI test automation. Mark 67 impossible-to-automate
tests RED in QA plan and scaffold initial Year View and Settings onboarding tests.

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

Tests iOS/YearViewDisplayTests.swift

@@ -0,0 +1,51 @@
+//
+//  YearViewDisplayTests.swift
+//  Tests iOS
+//
+//  Year View display tests: donut chart, bar chart.
+//  TC-035, TC-036
+//
+
+import XCTest
+
+final class YearViewDisplayTests: BaseUITestCase {
+    override var seedFixture: String? { "week_of_moods" }
+    override var bypassSubscription: Bool { true }
+
+    /// TC-035: Year View shows donut chart with mood distribution.
+    func testYearView_DonutChartVisible() {
+        let tabBar = TabBarScreen(app: app)
+        tabBar.tapYear()
+
+        // Wait for Year tab to be selected and content to load
+        XCTAssertTrue(tabBar.yearTab.isSelected, "Year tab should be selected")
+
+        captureScreenshot(name: "year_view_loaded")
+
+        // The donut chart is inside the stats section of the first YearCard.
+        // Try finding by accessibility identifier first, then fall back to presence of "days" text.
+        let donutChart = app.element(UITestID.Year.donutChart)
+        let found = donutChart.waitForExistence(timeout: 8) ||
+                    app.swipeUntilExists(donutChart, direction: .up, maxSwipes: 3, timeoutPerTry: 1.0)
+
+        captureScreenshot(name: "year_donut_chart")
+
+        XCTAssertTrue(found, "Donut chart should be visible in Year View")
+    }
+
+    /// TC-036: Year View shows bar chart with mood percentages.
+    func testYearView_BarChartVisible() {
+        let tabBar = TabBarScreen(app: app)
+        tabBar.tapYear()
+
+        XCTAssertTrue(tabBar.yearTab.isSelected, "Year tab should be selected")
+
+        let barChart = app.element(UITestID.Year.barChart)
+        let found = barChart.waitForExistence(timeout: 8) ||
+                    app.swipeUntilExists(barChart, direction: .up, maxSwipes: 3, timeoutPerTry: 1.0)
+
+        captureScreenshot(name: "year_bar_chart")
+
+        XCTAssertTrue(found, "Bar chart should be visible in Year View")
+    }
+}