Add saved payout destination UX and service contracts (#54)

frontend/packages/sxchnge_analytics/lib/sxchnge_analytics.dart

@@ -11,8 +11,11 @@ enum JourneyKind {
   exchange,
   payout,
   security,
+  destination,
 }
 
+enum DestinationResolution { created, duplicate }
+
 enum JourneyStep {
   login,
   signup,
@@ -23,6 +26,10 @@ enum JourneyStep {
   kycSelfie,
   kycSubmission,
   kycStatus,
+  destinationDraft,
+  destinationSave,
+  destinationReconciliation,
+  destinationBinding,
   transferDraft,
   transferQuote,
   transferSubmission,
@@ -78,6 +85,7 @@ class AnalyticsEvent {
     required this.sequence,
     required this.elapsedMs,
     this.step,
+    this.resolution,
     this.operation,
     this.failure,
     this.exit,
@@ -90,6 +98,7 @@ class AnalyticsEvent {
   final JourneyKind kind;
   final JourneySignal signal;
   final JourneyStep? step;
+  final DestinationResolution? resolution;
   final JourneyFailure? failure;
   final JourneyExit? exit;
   final int sequence;
@@ -105,6 +114,7 @@ class AnalyticsEvent {
       JourneyKind.exchange => 'exchange',
       JourneyKind.payout => 'payout',
       JourneyKind.security => 'security',
+      JourneyKind.destination => 'destination',
       _ => 'auth',
     };
     var stage = step == null ? 'journey' : _snake(step!.name);
@@ -123,6 +133,7 @@ class AnalyticsEvent {
     'terminal': terminal,
     'simulated': simulated,
     if (step != null) 'step': _snake(step!.name),
+    if (resolution != null) 'destination_resolution': resolution!.name,
     if (operation != null) 'operation': operation!,
     if (failure != null) 'failure': _snake(failure!.name),
     if (exit != null) 'exit': _snake(exit!.name),
@@ -210,6 +221,7 @@ class JourneyRecorder {
     JourneyFailure? failure,
     bool terminal = false,
     bool cancelled = false,
+    DestinationResolution? resolution,
   }) {
     final journey = operation._journey;
     if (_disposed || operation._finished || journey.closed) return;
@@ -227,6 +239,7 @@ class JourneyRecorder {
           ? JourneySignal.simulated
           : JourneySignal.succeeded,
       operation: operation,
+      resolution: resolution,
       failure: failure,
       terminal: complete,
       simulated: simulated || (complete && journey.simulated),
@@ -258,6 +271,7 @@ class JourneyRecorder {
     _Journey journey,
     JourneySignal signal, {
     JourneyOperation? operation,
+    DestinationResolution? resolution,
     JourneyFailure? failure,
     JourneyExit? exit,
     bool terminal = false,
@@ -271,6 +285,7 @@ class JourneyRecorder {
       sequence: ++journey.sequence,
       elapsedMs: journey.time.elapsedMilliseconds,
       step: operation?.step,
+      resolution: resolution,
       operation: operation?.number,
       failure: failure,
       exit: exit,