Redesign onboarding and paywall for 1.2.0

- Onboarding: replace feature-focused slides with outcome-focused copy
  ("Know exactly where you stand", "5 minutes a month is enough", etc.)
- Paywall: non-scrollable layout, reduce from 8 to 4 key benefits,
  remove transactional language (Unlock/Upgrade/Premium),
  new CTA "Get Full Access", floating close button
- Add IAPService.paywallBenefits for the condensed 4-item paywall list
- Update CompactPaywallBanner and PremiumLockOverlay copy

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

PortfolioJournal/Services/IAPService.swift

@@ -260,4 +260,12 @@ extension IAPService {
         ("xmark.circle", "No Ads", "Ad-free experience forever"),
         ("person.2", "Family Sharing", "Share with up to 5 family members")
     ]
+
+    /// Condensed benefits shown on the paywall (4 max, outcome-focused)
+    static let paywallBenefits: [(icon: String, title: String, subtitle: String)] = [
+        ("clock.arrow.circlepath", "Your complete history", "Every snapshot, contribution, and gain since day one"),
+        ("chart.bar.xaxis", "Charts that reveal patterns", "Allocation, drawdown, performance — all in one place"),
+        ("wand.and.stars", "12-month forecasts", "See where your portfolio is likely heading"),
+        ("xmark.circle", "No ads, ever", "Clean, focused experience with no distractions")
+    ]
 }