Fix remaining 12 UI test failures: subscription state, hittability, tab selection

- IAPManager: add resetForTesting() to discard stale cached subscription state
- UITestMode: call resetForTesting() after clearing defaults (fixes 5 banner tests)
- StabilityTests: use NSPredicate wait for isSelected (iOS 26 Liquid Glass)
- SettingsActionTests: use coordinate tap for clear data and analytics toggle
- IconPackTests: add horizontal scroll fallback for off-screen icon packs

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

Tests iOS/SettingsActionTests.swift

@@ -47,7 +47,7 @@ final class SettingsActionTests: BaseUITestCase {
             return
         }
 
-        clearButton.tap()
+        clearButton.coordinate(withNormalizedOffset: CGVector(dx: 0.5, dy: 0.5)).tap()
 
         // Navigate back to Day tab
         tabBar.tapDay()
@@ -94,7 +94,7 @@ final class SettingsActionTests: BaseUITestCase {
         }
 
         // Tap the toggle
-        analyticsToggle.tap()
+        analyticsToggle.coordinate(withNormalizedOffset: CGVector(dx: 0.5, dy: 0.5)).tap()
 
         captureScreenshot(name: "analytics_toggled")
     }