Release 1.3.0: onboarding UX, charts paywall banner, re-engagement notifications, Crashlytics

- Crashlytics: add FirebaseCrashlytics framework + dSYM upload build phase
- Onboarding: useSampleData off by default, Add First Investment as primary CTA
- AddSourceView: contextual placeholder and footer explaining what a source is
- Charts: CompactPaywallBanner visible to free users on every visit
- Notifications: re-engagement (7d) and monthly check-in local notifications
- Paywall: decorative chart preview replacing static crown icon
- Localization: all new strings in en + es-ES

PortfolioJournal/Views/Sources/AddSourceView.swift

@@ -39,7 +39,7 @@ struct AddSourceView: View {
 
                 // Source Info
                 Section {
-                    TextField("Source Name", text: $name)
+                    TextField(String(localized: "add_source_name_placeholder"), text: $name)
                         .textContentType(.organizationName)
                         .onChange(of: name) { _, newValue in
                             validateSourceName(newValue)
@@ -77,6 +77,9 @@ struct AddSourceView: View {
                     if let error = duplicateError {
                         Text(error)
                             .foregroundColor(.negativeRed)
+                    } else {
+                        Text(String(localized: "add_source_name_footer"))
+                            .foregroundColor(.secondary)
                     }
                 }