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>

Shared/UITestMode.swift

@@ -77,6 +77,10 @@ enum UITestMode {
 
         #if DEBUG
         IAPManager.shared.bypassSubscription = bypassSubscription
+        // Reset subscription state to discard stale cached state from previous test runs.
+        // IAPManager.shared was already initialized (as @StateObject in FeelsApp) before
+        // configureIfNeeded runs, so it may have restored stale subscription data.
+        IAPManager.shared.resetForTesting()
         #endif
 
         // Seed fixture data if requested