Add optional KYC flow and service-backed account limits

frontend/packages/sxchnge_analytics/lib/sxchnge_analytics.dart

@@ -2,11 +2,22 @@ import 'dart:async';
 import 'dart:collection';
 import 'dart:math';
 
-enum JourneyKind { login, signup, verification }
+enum JourneyKind { login, signup, verification, kyc }
 
-enum JourneyStep { login, signup, emailDelivery, emailConfirmation }
+enum JourneyStep {
+  login,
+  signup,
+  emailDelivery,
+  emailConfirmation,
+  kycPreparation,
+  kycPassport,
+  kycSelfie,
+  kycSubmission,
+  kycStatus,
+}
 
 enum JourneySignal {
+  cancelled,
   started,
   requested,
   succeeded,
@@ -16,6 +27,7 @@ enum JourneySignal {
 }
 
 enum JourneyFailure {
+  document,
   invalidCredentials,
   emailInUse,
   unavailable,
@@ -66,8 +78,13 @@ class AnalyticsEvent {
   final bool terminal;
   final bool simulated;
   final DateTime occurredAt;
-  String get name =>
-      'auth_${step == null ? 'journey' : _snake(step!.name)}_${signal.name}';
+  String get name {
+    final area = kind == JourneyKind.kyc ? 'kyc' : 'auth';
+    var stage = step == null ? 'journey' : _snake(step!.name);
+    if (kind == JourneyKind.kyc) stage = stage.replaceFirst('kyc_', '');
+    return '${area}_${stage}_${signal.name}';
+  }
+
   Map<String, Object> get properties => Map.unmodifiable({
     'schema_version': 1,
     'event_id': eventId,
@@ -165,16 +182,19 @@ class JourneyRecorder {
     bool simulated = false,
     JourneyFailure? failure,
     bool terminal = false,
+    bool cancelled = false,
   }) {
     final journey = operation._journey;
     if (_disposed || operation._finished || journey.closed) return;
     operation._finished = true;
     journey.pending--;
     journey.simulated |= simulated;
-    final complete = failure == null && terminal;
+    final complete = failure == null && !cancelled && terminal;
     _emit(
       journey,
-      failure != null
+      cancelled
+          ? JourneySignal.cancelled
+          : failure != null
           ? JourneySignal.failed
           : (simulated || (complete && journey.simulated))
           ? JourneySignal.simulated