feat: add PostHog analytics with full event tracking across app

Integrate self-hosted PostHog (SPM) with AnalyticsManager singleton wrapping
all SDK calls. Adds ~40 type-safe events covering trip planning, schedule,
progress, IAP, settings, polls, export, and share flows. Includes session
replay, autocapture, network telemetry, privacy opt-out toggle in Settings,
and super properties (app version, device, pro status, selected sports).

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

SportsTime/Features/Trip/Views/Wizard/TripWizardView.swift

@@ -165,6 +165,8 @@ struct TripWizardView: View {
     // MARK: - Planning
 
     private func planTrip() async {
+        let mode = viewModel.planningMode?.rawValue ?? "unknown"
+        AnalyticsManager.shared.track(.tripWizardStarted(mode: mode))
         viewModel.isPlanning = true
         defer { viewModel.isPlanning = false }
 
@@ -242,18 +244,29 @@ struct TripWizardView: View {
                 if options.isEmpty {
                     planningError = "No valid trip options found for your criteria. Try expanding your date range or regions."
                     showError = true
+                    AnalyticsManager.shared.track(.tripPlanFailed(mode: mode, error: "no_options_found"))
                 } else {
                     tripOptions = options
                     gamesForDisplay = richGamesDict
                     showTripOptions = true
+                    if let first = options.first {
+                        AnalyticsManager.shared.track(.tripPlanned(
+                            sportCount: viewModel.selectedSports.count,
+                            stopCount: first.stops.count,
+                            dayCount: first.stops.count,
+                            mode: mode
+                        ))
+                    }
                 }
             case .failure(let failure):
                 planningError = failure.message
                 showError = true
+                AnalyticsManager.shared.track(.tripPlanFailed(mode: mode, error: failure.message))
             }
         } catch {
             planningError = error.localizedDescription
             showError = true
+            AnalyticsManager.shared.track(.tripPlanFailed(mode: mode, error: error.localizedDescription))
         }
     }