fix: standardize trip name display with arrow separators app-wide

- Add `displayName` computed property to Trip model that always
  generates city list with " → " separator for consistent display
- Replace all `trip.name` usages with `trip.displayName` in UI files
- Update SuggestedTripsGenerator to use " → " separator
- Update PDFGenerator to use displayName for PDF titles

This ensures all trip names display consistently regardless of when
the trip was created or how the name was originally stored.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

SportsTime/Features/Home/Views/Variants/DarkIndustrial/HomeContent_DarkIndustrial.swift

@@ -306,7 +306,7 @@ struct HomeContent_DarkIndustrial: View {
                 .background(warningYellow)
 
             VStack(alignment: .leading, spacing: 6) {
-                Text(trip.name.uppercased())
+                Text(trip.displayName.uppercased())
                     .font(.system(size: 13, weight: .bold, design: .monospaced))
                     .foregroundStyle(textPrimary)
                     .lineLimit(1)
@@ -383,7 +383,7 @@ struct HomeContent_DarkIndustrial: View {
                                 .fill(steelGray.opacity(0.5))
                                 .frame(width: 3, height: 32)
 
-                            Text(trip.name.uppercased())
+                            Text(trip.displayName.uppercased())
                                 .font(.system(size: 12, weight: .medium, design: .monospaced))
                                 .foregroundStyle(textPrimary)