Fix FoundationModels crash, driving constraint, and disable card descriptions

- RouteDescriptionGenerator: reuse session, cap tokens at 60, greedy
  sampling, prewarm with prompt prefix, serial request queue with
  rate-limit retry and circuit breaker
- Disable AI/template descriptions on trip option cards
- GameDAGRouter: fix off-by-one in canTransition driving constraint
  (daysBetween+1) so multi-day cross-city routes aren't rejected
- CanonicalSyncService: wrap SyncStatusMonitor in #if DEBUG

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

SportsTime/Features/Trip/Views/TripOptionsView.swift

@@ -315,6 +315,7 @@ struct TripOptionsView: View {
             TripDetailView(trip: trip)
         }
         .onAppear {
+            RouteDescriptionGenerator.shared.prewarm()
             if isDemoMode && !hasAppliedDemoSelection {
                 hasAppliedDemoSelection = true
                 // Auto-select "Most Games" sort after a delay
@@ -491,7 +492,11 @@ struct TripOptionCard: View {
     @Environment(\.colorScheme) private var colorScheme
 
     @State private var aiDescription: String?
-    @State private var isLoadingDescription = false
+
+    private var templateDescription: String {
+        let input = RouteDescriptionInput(from: option, games: games)
+        return RouteDescriptionGenerator.shared.templateDescription(for: input)
+    }
 
     private var uniqueCities: [String] {
         option.stops.map { $0.city }.removingDuplicates()
@@ -571,21 +576,6 @@ struct TripOptionCard: View {
                         }
                     }
 
-                    // AI-generated description (after stats)
-                    if let description = aiDescription {
-                        Text(description)
-                            .font(.caption)
-                            .foregroundStyle(Theme.textMuted(colorScheme))
-                            .fixedSize(horizontal: false, vertical: true)
-                            .transition(.opacity)
-                    } else if isLoadingDescription {
-                        HStack(spacing: 4) {
-                            LoadingSpinner(size: .small)
-                            Text("Generating...")
-                                .font(.caption2)
-                                .foregroundStyle(Theme.textMuted(colorScheme))
-                        }
-                    }
                 }
 
                 Spacer()
@@ -606,28 +596,6 @@ struct TripOptionCard: View {
             }
         }
         .buttonStyle(.plain)
-        .task(id: option.id) {
-            // Reset state when option changes
-            aiDescription = nil
-            isLoadingDescription = false
-            await generateDescription()
-        }
-    }
-
-    private func generateDescription() async {
-        guard RouteDescriptionGenerator.shared.isAvailable else { return }
-
-        isLoadingDescription = true
-
-        // Build input from THIS specific option
-        let input = RouteDescriptionInput(from: option, games: games)
-
-        if let description = await RouteDescriptionGenerator.shared.generateDescription(for: input) {
-            Theme.Animation.withMotion(.easeInOut(duration: 0.3)) {
-                aiDescription = description
-            }
-        }
-        isLoadingDescription = false
     }
 }