feat(client/analytics): GA4 funnel instrumentation + unified home CTA

Add Firebase Analytics (GA4) funnel tracking to client_app:
- AnalyticsService typed wrapper (enum-gated, no PII) + analyticsProvider
- FirebaseAnalyticsObserver on GoRouter (screen_name via nameExtractor)
- user_id = customer UUID, user_type property, set on auth resolve/upgrade
- funnel events: curhat_start, curhat_repeat_start, auth_*, onboarding_usp_view,
  payment_view, payment_method_select, payment_started, pairing_matched/no_bestie
- bottom-sheet events: verif_choice_view/select, bestie_choice_view/select,
  extension_offer_view, chat_extension_requested
- payment_started carries app_instance_id + ga_session_id in the
  /payment-requests body for future server-side stitching (backend ignores)
- curhat_mode_pick screen name disambiguates the chat/call mode picker
  (/payment/method-pick) from the payment-channel picker (/payment/method)
- unify both home CTAs to "Aku Mau Curhat"

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

client_app/lib/core/analytics/analytics_service.dart

@@ -0,0 +1,254 @@
+import 'package:firebase_analytics/firebase_analytics.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+import '../../features/auth/widgets/verif_choice_sheet.dart' show VerifChoice;
+
+part 'analytics_service.g.dart';
+
+/// Which lifecycle funnel an event belongs to. GA4 reports filter on the
+/// `funnel` custom dimension; the activation and repeat funnels deliberately
+/// share event names and are split by this param (see
+/// requirement/analytics-funnel-plan.md §2/§5).
+enum AnalyticsFunnel {
+  activation('activation'),
+  repeat('repeat');
+
+  final String value;
+  const AnalyticsFunnel(this.value);
+}
+
+/// Identity method the user chose at the start of an auth flow. Low-cardinality
+/// and PII-free — the value is the *channel*, never the phone/email itself.
+enum AnalyticsAuthMethod {
+  phone('phone'),
+  google('google'),
+  apple('apple');
+
+  final String value;
+  const AnalyticsAuthMethod(this.value);
+}
+
+/// User-property bucket for `user_type`. Anonymous = server-issued anon
+/// customer with no identity; verified = phone/Google/Apple linked.
+enum AnalyticsUserType {
+  anonymous('anonymous'),
+  verified('verified');
+
+  final String value;
+  const AnalyticsUserType(this.value);
+}
+
+/// Stable screen names for the GoRouter observer. Keeping these as an enum
+/// (rather than mapping raw `state.uri.path`) guarantees path params like
+/// `:sessionId` / `:paymentId` / `:mitraId` never leak into `screen_name`.
+enum AnalyticsScreen {
+  splash('splash'),
+  authDisplayName('auth_display_name'),
+  authRegister('auth_register'),
+  authOtp('auth_otp'),
+  authSetName('auth_set_name'),
+  authForceRegister('auth_force_register'),
+  onboardingUspVerified('onboarding_usp_verified'),
+  onboardingUspAnon('onboarding_usp_anon'),
+  onboardingNotifGate('onboarding_notif_gate'),
+  home('home'),
+  profile('profile'),
+  paymentEntry('payment_entry'),
+  paymentDiscountPaywall('payment_discount_paywall'),
+  // Route /payment/method-pick is actually the chat-vs-call MODE picker
+  // ("pilih cara curhat"), NOT the payment-channel picker (that's
+  // paymentMethod → /payment/method). Named accordingly to avoid funnel
+  // ambiguity between the two.
+  curhatModePick('curhat_mode_pick'),
+  paymentDurationPick('payment_duration_pick'),
+  paymentMethod('payment_method'),
+  paymentWaiting('payment_waiting'),
+  paymentExpired('payment_expired'),
+  chatSearching('chat_searching'),
+  chatFound('chat_found'),
+  chatNoBestie('chat_no_bestie'),
+  chatWaitingTargeted('chat_waiting_targeted'),
+  chatSession('chat_session'),
+  chatThankYou('chat_thank_you'),
+  chatTabAktif('chat_tab_aktif'),
+  chatTabPembayaran('chat_tab_pembayaran'),
+  chatTabSelesai('chat_tab_selesai'),
+  chatTranscript('chat_transcript'),
+  bestieHistory('bestie_history');
+
+  final String value;
+  const AnalyticsScreen(this.value);
+}
+
+/// Thin, typed façade over `FirebaseAnalytics.instance`.
+///
+/// Every funnel event in requirement/analytics-funnel-plan.md §5 is a named
+/// method here so call sites never pass free-form strings — the only way to
+/// log is through a method whose params are fixed and PII-free. New events get
+/// added to the spec table first, then here (governance, §9).
+class AnalyticsService {
+  AnalyticsService(this._analytics);
+
+  final FirebaseAnalytics _analytics;
+
+  // ── Identity & user properties (§4) ───────────────────────────────────────
+
+  /// Set the opaque customer UUID. Re-set on identity upgrade (anon→verified)
+  /// so the same `user_id` continues across the merge. Never a phone/name.
+  Future<void> setUserId(String? customerId) =>
+      _analytics.setUserId(id: customerId);
+
+  Future<void> setUserType(AnalyticsUserType type) =>
+      _analytics.setUserProperty(name: 'user_type', value: type.value);
+
+  Future<void> setIsReturning(bool isReturning) => _analytics.setUserProperty(
+        name: 'is_returning',
+        value: isReturning ? 'true' : 'false',
+      );
+
+  // ── Payment stitching helpers (§3) ────────────────────────────────────────
+
+  /// App-instance id required by the GA4 Measurement Protocol to stitch a
+  /// server-fired `payment_confirmed` back to this device's stream.
+  Future<String?> appInstanceId() => _analytics.appInstanceId;
+
+  /// Current GA session id — replayed server-side so the MP event lands in the
+  /// same session as the client funnel.
+  Future<int?> sessionId() => _analytics.getSessionId();
+
+  // ── Funnel events (§5) ────────────────────────────────────────────────────
+
+  /// Activation: Home primary "aku mau curhat" CTA.
+  Future<void> logCurhatStart({String? entryPoint}) => _log('curhat_start', {
+        'funnel': AnalyticsFunnel.activation.value,
+        if (entryPoint != null) 'entry_point': entryPoint,
+      });
+
+  /// Repeat: returning "curhat sama bestie baru" / "curhat lagi" path.
+  Future<void> logCurhatRepeatStart() => _log('curhat_repeat_start', {
+        'funnel': AnalyticsFunnel.repeat.value,
+      });
+
+  /// Repeat: tapped a known bestie row in `/bestie/history`. `mitraRef` is an
+  /// opaque token (never the mitra's name/id surfaced to GA) — pass an
+  /// already-hashed/short ref or omit.
+  Future<void> logBestieReselect({String? mitraRef}) => _log('bestie_reselect', {
+        'funnel': AnalyticsFunnel.repeat.value,
+        if (mitraRef != null) 'mitra_ref': mitraRef,
+      });
+
+  Future<void> logAuthStart(AnalyticsAuthMethod method) => _log('auth_start', {
+        'method': method.value,
+      });
+
+  Future<void> logAuthOtpSubmit() => _log('auth_otp_submit', const {});
+
+  Future<void> logAuthComplete(AnalyticsUserType userType) =>
+      _log('auth_complete', {'user_type': userType.value});
+
+  Future<void> logOnboardingUspView({required bool verified}) =>
+      _log('onboarding_usp_view', {'verified': verified});
+
+  Future<void> logPaymentView({
+    required AnalyticsFunnel funnel,
+    required bool isRepeat,
+  }) =>
+      _log('payment_view', {
+        'funnel': funnel.value,
+        'is_repeat': isRepeat,
+      });
+
+  Future<void> logPaymentMethodSelect({required String method}) =>
+      _log('payment_method_select', {'method': method});
+
+  /// ⭐ Fired only AFTER the POST /payment-requests returns an id.
+  Future<void> logPaymentStarted({
+    required String paymentRequestId,
+    required int amount,
+    required String method,
+    required AnalyticsFunnel funnel,
+    required bool isRepeat,
+    required String productType,
+    required int durationMinutes,
+    String currency = 'IDR',
+  }) =>
+      _log('payment_started', {
+        'payment_request_id': paymentRequestId,
+        'amount': amount,
+        'currency': currency,
+        'method': method,
+        'funnel': funnel.value,
+        'is_repeat': isRepeat,
+        'product_type': productType,
+        'duration_minutes': durationMinutes,
+      });
+
+  Future<void> logPairingMatched({required AnalyticsFunnel funnel}) =>
+      _log('pairing_matched', {'funnel': funnel.value});
+
+  Future<void> logPairingNoBestie({required AnalyticsFunnel funnel}) =>
+      _log('pairing_no_bestie', {'funnel': funnel.value});
+
+  // ── Bottom-sheet / modal funnel events (§5) ───────────────────────────────
+
+  /// Activation: post-name Verif Choice Sheet shown. Paired with
+  /// [logVerifChoiceSelect] — the gap between view and select is abandonment.
+  Future<void> logVerifChoiceView() =>
+      _log('verif_choice_view', const {});
+
+  /// Activation: user picked an identity branch in the Verif Choice Sheet.
+  /// Maps the [VerifChoice] enum to a low-cardinality, PII-free channel value.
+  Future<void> logVerifChoiceSelect(VerifChoice choice) =>
+      _log('verif_choice_select', {
+        'choice': switch (choice) {
+          VerifChoice.verified => 'verified',
+          VerifChoice.anonymous => 'anonymous',
+        },
+      });
+
+  /// Repeat: Bestie Choice Sheet shown from the returning-user Home CTA.
+  Future<void> logBestieChoiceView() =>
+      _log('bestie_choice_view', const {});
+
+  /// Repeat: user picked a bestie branch in the Bestie Choice Sheet.
+  Future<void> logBestieChoiceSelect({required bool knownBestie}) =>
+      _log('bestie_choice_select', {
+        'choice': knownBestie ? 'known_bestie' : 'new_bestie',
+      });
+
+  /// Repeat: in-session extension upsell sheet shown (time-up / low-time).
+  Future<void> logExtensionOfferView({String? sessionId}) =>
+      _log('extension_offer_view', {
+        if (sessionId != null) 'session_id': sessionId,
+      });
+
+  /// Repeat: user confirmed an extension from the upsell sheet (not dismiss
+  /// or "akhiri sesi"). Fired the moment the perpanjang CTA is committed.
+  Future<void> logChatExtensionRequested({String? sessionId}) =>
+      _log('chat_extension_requested', {
+        if (sessionId != null) 'session_id': sessionId,
+      });
+
+  // ── Internal ──────────────────────────────────────────────────────────────
+
+  Future<void> _log(String name, Map<String, Object?> params) async {
+    final clean = <String, Object>{
+      for (final e in params.entries)
+        if (e.value != null) e.key: e.value!,
+    };
+    try {
+      await _analytics.logEvent(name: name, parameters: clean.isEmpty ? null : clean);
+    } catch (e) {
+      // Analytics must never break a user flow.
+      debugPrint('[analytics] failed to log $name: $e');
+    }
+  }
+}
+
+/// Keep-alive so a single AnalyticsService (and its FirebaseAnalytics handle)
+/// is shared across screens/notifiers for the app's lifetime.
+@Riverpod(keepAlive: true)
+AnalyticsService analytics(Ref ref) =>
+    AnalyticsService(FirebaseAnalytics.instance);

client_app/lib/core/analytics/analytics_service.g.dart

@@ -0,0 +1,29 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'analytics_service.dart';
+
+// **************************************************************************
+// RiverpodGenerator
+// **************************************************************************
+
+String _$analyticsHash() => r'862f59acd499543968f9ee591cec55cdd1b50035';
+
+/// Keep-alive so a single AnalyticsService (and its FirebaseAnalytics handle)
+/// is shared across screens/notifiers for the app's lifetime.
+///
+/// Copied from [analytics].
+@ProviderFor(analytics)
+final analyticsProvider = Provider<AnalyticsService>.internal(
+  analytics,
+  name: r'analyticsProvider',
+  debugGetCreateSourceHash:
+      const bool.fromEnvironment('dart.vm.product') ? null : _$analyticsHash,
+  dependencies: null,
+  allTransitiveDependencies: null,
+);
+
+@Deprecated('Will be removed in 3.0. Use Ref instead')
+// ignore: unused_element
+typedef AnalyticsRef = ProviderRef<AnalyticsService>;
+// ignore_for_file: type=lint
+// ignore_for_file: subtype_of_sealed_class, invalid_use_of_internal_member, invalid_use_of_visible_for_testing_member, deprecated_member_use_from_same_package

client_app/lib/core/auth/auth_notifier.g.dart

@@ -6,7 +6,7 @@ part of 'auth_notifier.dart';
 // RiverpodGenerator
 // **************************************************************************
 
-String _$authHash() => r'f0382b1380749cebe8182ad221023926768ebb92';
+String _$authHash() => r'76cd43babe5503d35a35c8fd23ba32afbc4c8c2d';
 
 /// See also [Auth].
 @ProviderFor(Auth)

client_app/lib/core/chat/chat_notifier.g.dart

@@ -30,7 +30,7 @@ final chatRemainingSecondsProvider = AutoDisposeStreamProvider<int>.internal(
 @Deprecated('Will be removed in 3.0. Use Ref instead')
 // ignore: unused_element
 typedef ChatRemainingSecondsRef = AutoDisposeStreamProviderRef<int>;
-String _$chatHash() => r'a42bf404f5b38034c6c9511259b64b1092af3caa';
+String _$chatHash() => r'56f019ce6e527128ab42a71f56220c5412cfec0f';
 
 /// See also [Chat].
 @ProviderFor(Chat)

client_app/lib/core/chat/session_closure_notifier.g.dart

@@ -6,7 +6,7 @@ part of 'session_closure_notifier.dart';
 // RiverpodGenerator
 // **************************************************************************
 
-String _$sessionClosureHash() => r'a9aaf26da64d3489497d057e2b05741c08444e07';
+String _$sessionClosureHash() => r'1ab9df044138115e232b3df494e2895177d9d66d';
 
 /// See also [SessionClosure].
 @ProviderFor(SessionClosure)

client_app/lib/core/pairing/pairing_notifier.g.dart

@@ -6,7 +6,7 @@ part of 'pairing_notifier.dart';
 // RiverpodGenerator
 // **************************************************************************
 
-String _$pairingHash() => r'd39980fe5b82348d03485006d0534ab597b93ceb';
+String _$pairingHash() => r'e66bbf67e1013b3d25230ed01fe2595bff943b3a';
 
 /// See also [Pairing].
 @ProviderFor(Pairing)

client_app/lib/features/auth/screens/display_name_screen.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/api/api_client_provider.dart';
 import '../../../core/auth/auth_notifier.dart';
 import '../../../core/theme/halo_tokens.dart';
@@ -35,6 +36,9 @@ class _DisplayNameScreenState extends ConsumerState<DisplayNameScreen> {
       final data = next.valueOrNull;
       if (data is AuthAnonymousData && !_routedAfterLogin) {
         _routedAfterLogin = true;
+        // Anonymous identity established — activation step 6.
+        // ignore: discarded_futures
+        ref.read(analyticsProvider).logAuthComplete(AnalyticsUserType.anonymous);
         _proceedAfterLogin();
       }
     });
@@ -82,12 +86,17 @@ class _DisplayNameScreenState extends ConsumerState<DisplayNameScreen> {
       return;
     }
 
+    // ignore: discarded_futures
+    ref.read(analyticsProvider).logVerifChoiceView();
     final choice = await VerifChoiceSheet.show(context);
     if (!mounted || choice == null) {
-      // User dismissed the sheet — let them tap Lanjut again to retry.
+      // User dismissed the sheet — let them tap Lanjut again to retry. No
+      // select event: the view→select gap is the abandonment signal.
       _routedAfterLogin = false;
       return;
     }
+    // ignore: discarded_futures
+    ref.read(analyticsProvider).logVerifChoiceSelect(choice);
     if (!mounted) return;
     await routeForVerifChoice(context, ref, choice);
   }

client_app/lib/features/auth/screens/otp_screen.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/api/api_client_provider.dart';
 import '../../../core/auth/auth_notifier.dart';
 import '../../../core/constants.dart';
@@ -75,6 +76,14 @@ class _OtpScreenState extends ConsumerState<OtpScreen> {
         if (_errorMessage != null && mounted) {
           setState(() => _errorMessage = null);
         }
+        // OTP verify resolved to a real identity — activation/repeat step 6.
+        final data = next.valueOrNull;
+        if (data is AuthAuthenticatedData || data is AuthNeedsDisplayNameData) {
+          // ignore: discarded_futures
+          ref
+              .read(analyticsProvider)
+              .logAuthComplete(AnalyticsUserType.verified);
+        }
       }
     });
 
@@ -152,6 +161,8 @@ class _OtpScreenState extends ConsumerState<OtpScreen> {
     final code = _readCode();
     if (code.length == _kOtpLength && !_autoSubmitted && _otpRequestId != null) {
       _autoSubmitted = true;
+      // ignore: discarded_futures
+      ref.read(analyticsProvider).logAuthOtpSubmit();
       ref.read(authProvider.notifier).verifyOtp(_otpRequestId!, code);
     }
   }

client_app/lib/features/auth/screens/register_screen.dart

@@ -3,6 +3,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/auth/auth_notifier.dart';
 import '../../../core/constants.dart';
 import '../../../core/theme/halo_tokens.dart';
@@ -222,8 +223,15 @@ class _RegisterScreenState extends ConsumerState<RegisterScreen> {
                         : 'kirim kode',
                 fullWidth: true,
                 onPressed: canSubmit
-                    ? () =>
-                        ref.read(authProvider.notifier).requestOtp(_e164Phone())
+                    ? () {
+                        // ignore: discarded_futures
+                        ref
+                            .read(analyticsProvider)
+                            .logAuthStart(AnalyticsAuthMethod.phone);
+                        ref
+                            .read(authProvider.notifier)
+                            .requestOtp(_e164Phone());
+                      }
                     : null,
               ),
               if (!fromProfile) ...[

client_app/lib/features/chat/screens/bestie_found_screen.dart

@@ -1,9 +1,11 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/chat/active_session_notifier.dart';
 import '../../../core/pairing/pairing_notifier.dart';
 import '../../../core/theme/halo_tokens.dart';
+import '../../payment/state/payment_draft_provider.dart';
 import '../../../core/theme/widgets/widgets.dart';
 
 /// Phase 4 Stage 5 — S9 Match-found screen.
@@ -35,6 +37,15 @@ class _BestieFoundScreenState extends ConsumerState<BestieFoundScreen> {
   @override
   void initState() {
     super.initState();
+    // Funnel step 12 — paired with a mitra. A targeted-mitra draft means the
+    // repeat funnel; otherwise activation. Fire once on view.
+    final isRepeat =
+        ref.read(paymentDraftNotifierProvider).targetedMitraId != null;
+    // ignore: discarded_futures
+    ref.read(analyticsProvider).logPairingMatched(
+          funnel:
+              isRepeat ? AnalyticsFunnel.repeat : AnalyticsFunnel.activation,
+        );
     ref.listenManual<PairingData>(pairingProvider, (prev, next) {
       if (!mounted) return;
       if (next is PairingActiveData) {

client_app/lib/features/chat/screens/chat_screen.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/chat/active_session_notifier.dart';
 import '../../../core/chat/chat_notifier.dart';
 import '../../../core/chat/session_closure_notifier.dart';
@@ -512,6 +513,8 @@ class _TimerBanner extends ConsumerWidget {
       return _BannerKind.none;
     }));
     void onExtend() {
+      // ignore: discarded_futures
+      ref.read(analyticsProvider).logExtensionOfferView(sessionId: sessionId);
       PricingBottomSheet.showForExtension(
         context,
         sessionId: sessionId,

client_app/lib/features/chat/screens/no_bestie_screen.dart

@@ -1,7 +1,9 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/pairing/pairing_notifier.dart';
+import '../../payment/state/payment_draft_provider.dart';
 
 /// Terminal failed-pairing screen.
 ///
@@ -13,11 +15,30 @@ import '../../../core/pairing/pairing_notifier.dart';
 /// Single CTA "Kembali ke beranda" resets the pairing notifier and routes
 /// home. PopScope falls back to home for deep-link entry per project memory
 /// rule "Deep-link pop fallback".
-class NoBestieScreen extends ConsumerWidget {
+class NoBestieScreen extends ConsumerStatefulWidget {
   const NoBestieScreen({super.key});
 
   @override
-  Widget build(BuildContext context, WidgetRef ref) {
+  ConsumerState<NoBestieScreen> createState() => _NoBestieScreenState();
+}
+
+class _NoBestieScreenState extends ConsumerState<NoBestieScreen> {
+  @override
+  void initState() {
+    super.initState();
+    // Funnel drop-off marker — pairing failed. A targeted-mitra draft means
+    // the repeat funnel; otherwise activation. Fire once on view.
+    final isRepeat =
+        ref.read(paymentDraftNotifierProvider).targetedMitraId != null;
+    // ignore: discarded_futures
+    ref.read(analyticsProvider).logPairingNoBestie(
+          funnel:
+              isRepeat ? AnalyticsFunnel.repeat : AnalyticsFunnel.activation,
+        );
+  }
+
+  @override
+  Widget build(BuildContext context) {
     return PopScope(
       canPop: true,
       onPopInvokedWithResult: (didPop, _) {

client_app/lib/features/chat/widgets/pricing_bottom_sheet.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/chat/chat_opening_provider.dart';
 import '../../../core/chat/session_closure_notifier.dart';
 import '../../../core/constants.dart';
@@ -85,6 +86,10 @@ class _PricingBottomSheetState extends ConsumerState<PricingBottomSheet> {
   }
 
   void _onConfirm(PriceTier tier) {
+    // ignore: discarded_futures
+    ref.read(analyticsProvider).logChatExtensionRequested(
+          sessionId: widget.extensionSessionId,
+        );
     Navigator.of(context).pop();
     ref.read(sessionClosureProvider.notifier).requestExtension(
           widget.extensionSessionId,

client_app/lib/features/home/home_screen.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../core/analytics/analytics_service.dart';
 import '../../core/auth/auth_notifier.dart';
 import '../../core/auth/onboarding_intent_provider.dart';
 import '../../core/availability/mitra_availability_notifier.dart';
@@ -81,6 +82,11 @@ class _HomeScreenState extends ConsumerState<HomeScreen> with WidgetsBindingObse
   /// CTA path for SHomeReturning. Returning users get the bestie-choice sheet
   /// when they have prior history, otherwise jump to the new-payment shell.
   Future<void> _onCurhatBestieBaruPressed(BuildContext context) async {
+    // Returning user starting a fresh curhat (repeat funnel). The
+    // bestie_reselect sub-event fires later from the history list if they pick
+    // a known bestie; this marks the top of the repeat funnel.
+    // ignore: discarded_futures
+    ref.read(analyticsProvider).logCurhatRepeatStart();
     bool hasHistory;
     try {
       hasHistory = await ref.read(bestieHistoryHasItemsProvider.future);
@@ -89,6 +95,8 @@ class _HomeScreenState extends ConsumerState<HomeScreen> with WidgetsBindingObse
     }
     if (!context.mounted) return;
     if (hasHistory) {
+      // ignore: discarded_futures
+      ref.read(analyticsProvider).logBestieChoiceView();
       await BestieChoiceSheet.show(context);
       return;
     }
@@ -101,6 +109,9 @@ class _HomeScreenState extends ConsumerState<HomeScreen> with WidgetsBindingObse
   /// (the call-sign check); display_name_screen kicks off `loginAnonymous`
   /// and pushes into the verif-choice sheet.
   void _onAkuMauCurhatPressed(BuildContext context) {
+    // Top of the activation funnel — fresh user tapping the primary CTA.
+    // ignore: discarded_futures
+    ref.read(analyticsProvider).logCurhatStart(entryPoint: 'home_primary');
     context.push('/auth/display-name');
   }
 
@@ -172,7 +183,7 @@ class _SHome1stView extends ConsumerWidget {
               const _GreetingSubtitle(),
               const SizedBox(height: 32),
               _PrimaryCTA(
-                label: 'aku mau curhat',
+                label: 'Aku Mau Curhat',
                 enabled: mitraAvailable,
                 onPressed: onCTA,
               ),
@@ -395,7 +406,7 @@ class _SHomeReturningView extends ConsumerWidget {
         activeSessionAsync.when(
           loading: () => const Center(child: CircularProgressIndicator()),
           error: (_, __) => _PrimaryCTA(
-            label: 'curhat sama bestie baru',
+            label: 'Aku Mau Curhat',
             enabled: mitraAvailable,
             onPressed: onCTA,
           ),
@@ -415,7 +426,7 @@ class _SHomeReturningView extends ConsumerWidget {
               );
             }
             return _PrimaryCTA(
-              label: 'curhat sama bestie baru',
+              label: 'Aku Mau Curhat',
               enabled: mitraAvailable,
               onPressed: onCTA,
             );

client_app/lib/features/home/screens/bestie_history_list_screen.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/constants.dart';
 import '../../../core/theme/halo_tokens.dart';
 import '../../../core/theme/widgets/widgets.dart';
@@ -132,6 +133,13 @@ class BestieHistoryListScreen extends ConsumerWidget {
                       return;
                     }
                     if (item.mitraId == null) return;
+                    // Repeat funnel: user re-selected a known bestie. mitra_ref
+                    // is opaque (hashed) — never the raw mitra id, per the
+                    // no-PII / opaque-mitra-identity rule.
+                    // ignore: discarded_futures
+                    ref.read(analyticsProvider).logBestieReselect(
+                          mitraRef: item.mitraId!.hashCode.toString(),
+                        );
                     // Stamp the targeted mitra onto the payment draft; the
                     // multi-screen payment flow (entry → method → waiting →
                     // notif-gate → searching) reads it back to fire the

client_app/lib/features/home/widgets/bestie_choice_sheet.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/theme/halo_tokens.dart';
 import '../../../core/theme/widgets/widgets.dart';
 import '../../payment/state/payment_draft_provider.dart';
@@ -52,6 +53,8 @@ class BestieChoiceSheet extends ConsumerWidget {
           subtitle: 'lanjut cerita ke bestie yang pernah dengerin kamu.',
           icon: Icons.favorite_outline,
           onTap: () {
+            // ignore: discarded_futures
+            ref.read(analyticsProvider).logBestieChoiceSelect(knownBestie: true);
             Navigator.of(context).pop();
             context.push('/bestie/history');
           },
@@ -62,6 +65,8 @@ class BestieChoiceSheet extends ConsumerWidget {
           subtitle: 'cari bestie baru yang siap dengerin sekarang.',
           icon: Icons.auto_awesome_outlined,
           onTap: () {
+            // ignore: discarded_futures
+            ref.read(analyticsProvider).logBestieChoiceSelect(knownBestie: false);
             // explicit reset — this branch is blast-only, clear any stale targeted mitra
             ref.read(paymentDraftNotifierProvider.notifier).reset();
             Navigator.of(context).pop();

client_app/lib/features/onboarding/screens/usp_screen.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/theme/halo_tokens.dart';
 import '../../../core/theme/widgets/widgets.dart';
 import '../usp_seen_provider.dart';
@@ -11,11 +12,30 @@ import '../usp_seen_provider.dart';
 ///
 /// `verified` ➞ USP → OTP (`/auth/register`).
 /// `anonymous` ➞ USP → `/payment/method-pick`.
-class UspScreen extends ConsumerWidget {
+class UspScreen extends ConsumerStatefulWidget {
   final bool verified;
 
   const UspScreen({super.key, required this.verified});
 
+  @override
+  ConsumerState<UspScreen> createState() => _UspScreenState();
+}
+
+class _UspScreenState extends ConsumerState<UspScreen> {
+  @override
+  void initState() {
+    super.initState();
+    // Activation funnel step 7 — fire on view (not teardown). One-shot:
+    // initState runs once per screen instance.
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
+      // ignore: discarded_futures
+      ref
+          .read(analyticsProvider)
+          .logOnboardingUspView(verified: widget.verified);
+    });
+  }
+
   static const _cards = [
     _UspCard(
       icon: Icons.bolt_outlined,
@@ -40,7 +60,7 @@ class UspScreen extends ConsumerWidget {
   ];
 
   @override
-  Widget build(BuildContext context, WidgetRef ref) {
+  Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
         title: const Padding(
@@ -94,7 +114,7 @@ class UspScreen extends ConsumerWidget {
               HaloButton(
                 label: 'aku ngerti, lanjut',
                 fullWidth: true,
-                onPressed: () => _onContinue(context, ref),
+                onPressed: () => _onContinue(context),
               ),
             ],
           ),
@@ -103,12 +123,12 @@ class UspScreen extends ConsumerWidget {
     );
   }
 
-  Future<void> _onContinue(BuildContext context, WidgetRef ref) async {
+  Future<void> _onContinue(BuildContext context) async {
     // Persist the local + server flag before leaving — next time the user
     // hits VerifChoice, this screen is skipped.
     await ref.read(uspSeenProvider.notifier).markSeen();
     if (!context.mounted) return;
-    if (verified) {
+    if (widget.verified) {
       context.push('/auth/register');
     } else {
       context.push('/payment/method-pick');

client_app/lib/features/payment/screens/payment_entry_screen.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/auth/onboarding_intent_provider.dart';
 import '../../../core/chat/chat_opening_provider.dart';
 import '../../../core/theme/halo_tokens.dart';
@@ -38,6 +39,18 @@ class _PaymentEntryScreenState extends ConsumerState<PaymentEntryScreen> {
       // inherit a stale onboarding intent.
       ref.read(onboardingIntentProvider.notifier).state =
           OnboardingIntent.recover;
+
+      // Funnel step 8 — payment entry. A targeted mitra (set just before this
+      // screen by the bestie-history list) marks the repeat funnel; otherwise
+      // it's activation. resetExceptTarget() above preserves that flag.
+      final isRepeat =
+          ref.read(paymentDraftNotifierProvider).targetedMitraId != null;
+      // ignore: discarded_futures
+      ref.read(analyticsProvider).logPaymentView(
+            funnel:
+                isRepeat ? AnalyticsFunnel.repeat : AnalyticsFunnel.activation,
+            isRepeat: isRepeat,
+          );
     });
   }
 

client_app/lib/features/payment/screens/payment_method_screen.dart

@@ -2,6 +2,7 @@ import 'package:dio/dio.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import '../../../core/analytics/analytics_service.dart';
 import '../../../core/api/api_client_provider.dart';
 import '../../../core/constants.dart';
 import '../../../core/theme/halo_tokens.dart';
@@ -53,7 +54,21 @@ class _PaymentMethodScreenState extends ConsumerState<PaymentMethodScreen> {
       _error = null;
     });
     final api = ref.read(apiClientProvider);
+    final analytics = ref.read(analyticsProvider);
     try {
+      // ⭐ Capture GA4 stitching identifiers BEFORE the POST so the backend can
+      // store them in product_metadata and replay them in the server-fired
+      // payment_confirmed (Measurement Protocol). The backend currently
+      // ignores unknown body fields — intentional; we send now, stitch later.
+      final appInstanceId = await analytics.appInstanceId();
+      final gaSessionId = await analytics.sessionId();
+      if (!mounted) return;
+
+      final analyticsIds = <String, dynamic>{
+        if (appInstanceId != null) 'app_instance_id': appInstanceId,
+        if (gaSessionId != null) 'ga_session_id': gaSessionId,
+      };
+
       final body = <String, dynamic>{
         'mode': draft.mode.value,
         'duration_minutes': draft.durationMinutes,
@@ -61,11 +76,27 @@ class _PaymentMethodScreenState extends ConsumerState<PaymentMethodScreen> {
         'is_first_session_discount': draft.isFirstSessionDiscount,
         'method': _selectedCode,
         if (draft.targetedMitraId != null) 'targeted_mitra_id': draft.targetedMitraId,
+        if (analyticsIds.isNotEmpty) 'analytics': analyticsIds,
       };
       final response = await api.post('/api/client/payment-requests/', data: body);
       final data = response['data'] as Map<String, dynamic>;
       final paymentId = data['id'] as String;
       ref.read(paymentDraftNotifierProvider.notifier).setPaymentId(paymentId);
+
+      // ⭐ payment_started fires AFTER the id is known. A targeted mitra means
+      // the returning/repeat funnel; otherwise activation.
+      final isRepeat = draft.targetedMitraId != null;
+      // ignore: discarded_futures
+      analytics.logPaymentStarted(
+        paymentRequestId: paymentId,
+        amount: draft.priceIDR!,
+        method: _selectedCode!,
+        funnel: isRepeat ? AnalyticsFunnel.repeat : AnalyticsFunnel.activation,
+        isRepeat: isRepeat,
+        productType: draft.mode.value,
+        durationMinutes: draft.durationMinutes!,
+      );
+
       if (!mounted) return;
       context.push('/payment/waiting/$paymentId');
     } on DioException catch (e) {
@@ -216,10 +247,20 @@ class _PaymentMethodScreenState extends ConsumerState<PaymentMethodScreen> {
                           _expandedGroupIds.remove(g.id);
                         }
                       }),
-                      onSelect: (code) => setState(() {
-                        _selectedCode = code;
-                        _error = null;
-                      }),
+                      onSelect: (code) {
+                        // Funnel step 9 — method chosen. Fire once per pick
+                        // (not on every rebuild).
+                        if (code != _selectedCode) {
+                          // ignore: discarded_futures
+                          ref
+                              .read(analyticsProvider)
+                              .logPaymentMethodSelect(method: code);
+                        }
+                        setState(() {
+                          _selectedCode = code;
+                          _error = null;
+                        });
+                      },
                     );
                   }).toList(),
                 );

client_app/lib/features/payment/state/payment_draft_provider.g.dart

@@ -7,7 +7,7 @@ part of 'payment_draft_provider.dart';
 // **************************************************************************
 
 String _$paymentDraftNotifierHash() =>
-    r'1c81b22f25f525cd290f54618bee0b69de792998';
+    r'e489a593f5e1cc2794d13566a9cf960bb89e45c6';
 
 /// See also [PaymentDraftNotifier].
 @ProviderFor(PaymentDraftNotifier)

client_app/lib/main.dart

@@ -1,9 +1,11 @@
 import 'dart:async';
 
+import 'package:firebase_analytics/firebase_analytics.dart';
 import 'package:firebase_core/firebase_core.dart';
 import 'package:firebase_messaging/firebase_messaging.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'core/analytics/analytics_service.dart';
 import 'core/api/api_client_provider.dart';
 import 'core/auth/auth_notifier.dart';
 import 'core/auth/auth_providers_provider.dart';
@@ -28,6 +30,12 @@ void main() async {
 
   await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
 
+  // Enable GA4 collection. Fire-and-forget so it never adds to cold-start
+  // latency; the SDK queues events until collection is on.
+  unawaited(
+    FirebaseAnalytics.instance.setAnalyticsCollectionEnabled(true),
+  );
+
   final messaging = FirebaseMessaging.instance;
   await messaging.requestPermission();
 
@@ -131,9 +139,41 @@ class _AppState extends ConsumerState<App> with WidgetsBindingObserver {
     });
   }
 
+  // Tracks the last user_id pushed to GA4 so we don't re-issue identical
+  // setUserId/user-property calls on every transient auth emission.
+  String? _analyticsUserId;
+
+  /// Mirror auth state into GA4 identity (§4): opaque customer UUID as
+  /// `user_id` + `user_type` property. Re-set on identity upgrade
+  /// (anon→verified) so the same user continues. Never sets phone/name.
+  void _syncAnalyticsIdentity(AuthData? data) {
+    final analytics = ref.read(analyticsProvider);
+    final (String? customerId, AnalyticsUserType? userType) = switch (data) {
+      AuthAnonymousData d => (d.customerId, AnalyticsUserType.anonymous),
+      AuthForceRegisterData d => (d.customerId, AnalyticsUserType.anonymous),
+      AuthAuthenticatedData d => (
+          d.profile['id'] as String?,
+          AnalyticsUserType.verified,
+        ),
+      AuthNeedsDisplayNameData d => (
+          d.profile['id'] as String?,
+          AnalyticsUserType.verified,
+        ),
+      _ => (null, null),
+    };
+    if (customerId == _analyticsUserId) return;
+    _analyticsUserId = customerId;
+    // ignore: discarded_futures
+    analytics.setUserId(customerId);
+    if (userType != null) {
+      // ignore: discarded_futures
+      analytics.setUserType(userType);
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
-    // FCM registration on auth.
+    // FCM registration + analytics identity on auth.
     ref.listen(authProvider, (prev, next) {
       final data = next.valueOrNull;
       if (data is AuthAuthenticatedData || data is AuthAnonymousData) {
@@ -142,6 +182,7 @@ class _AppState extends ConsumerState<App> with WidgetsBindingObserver {
         // Logged out (or initial) — ensure the chat WS is closed.
         ref.read(chatProvider.notifier).disconnect();
       }
+      _syncAnalyticsIdentity(data);
     });
 
     // Global chat WebSocket lifecycle: connect whenever the user has an

client_app/lib/router.dart

@@ -1,6 +1,8 @@
+import 'package:firebase_analytics/firebase_analytics.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import 'core/analytics/analytics_service.dart';
 import 'core/auth/auth_notifier.dart';
 import 'core/auth/onboarding_intent_provider.dart';
 import 'features/auth/screens/display_name_screen.dart';
@@ -54,12 +56,62 @@ class RouterNotifier extends ChangeNotifier {
 
 final routerProvider = Provider<GoRouter>((ref) => buildRouter(ref));
 
+/// Maps a GoRoute path template (`Route.settings.name`) to a stable
+/// `screen_name`. Keyed on the *template* (e.g. `/chat/session/:sessionId`)
+/// so path params are never part of the logged name. Routes absent here are
+/// dropped (return null → observer skips the screen_view).
+const _screenNameByRoute = <String, AnalyticsScreen>{
+  '/splash': AnalyticsScreen.splash,
+  '/auth/display-name': AnalyticsScreen.authDisplayName,
+  '/auth/register': AnalyticsScreen.authRegister,
+  '/auth/otp': AnalyticsScreen.authOtp,
+  '/auth/set-name': AnalyticsScreen.authSetName,
+  '/auth/force-register': AnalyticsScreen.authForceRegister,
+  '/onboarding/verif/usp': AnalyticsScreen.onboardingUspVerified,
+  '/onboarding/anon/usp': AnalyticsScreen.onboardingUspAnon,
+  '/onboarding/notif-gate': AnalyticsScreen.onboardingNotifGate,
+  '/home': AnalyticsScreen.home,
+  '/profile': AnalyticsScreen.profile,
+  '/payment/entry': AnalyticsScreen.paymentEntry,
+  '/payment/discount-paywall': AnalyticsScreen.paymentDiscountPaywall,
+  '/payment/method-pick': AnalyticsScreen.curhatModePick,
+  '/payment/duration-pick': AnalyticsScreen.paymentDurationPick,
+  '/payment/method': AnalyticsScreen.paymentMethod,
+  '/payment/waiting/:paymentId': AnalyticsScreen.paymentWaiting,
+  '/payment/expired/:paymentId': AnalyticsScreen.paymentExpired,
+  '/chat/searching': AnalyticsScreen.chatSearching,
+  '/chat/found': AnalyticsScreen.chatFound,
+  '/chat/no-bestie': AnalyticsScreen.chatNoBestie,
+  '/chat/waiting-targeted/:mitraId': AnalyticsScreen.chatWaitingTargeted,
+  '/chat/session/:sessionId': AnalyticsScreen.chatSession,
+  '/chat/thank-you': AnalyticsScreen.chatThankYou,
+  '/chat/aktif': AnalyticsScreen.chatTabAktif,
+  '/chat/pembayaran': AnalyticsScreen.chatTabPembayaran,
+  '/chat/selesai': AnalyticsScreen.chatTabSelesai,
+  '/chat/transcript/:sessionId': AnalyticsScreen.chatTranscript,
+  '/bestie/history': AnalyticsScreen.bestieHistory,
+};
+
+/// `nameExtractor` for [FirebaseAnalyticsObserver]. GoRouter sets
+/// `Route.settings.name` to the route's path template, so this strips path
+/// params (`:sessionId` etc.) by construction.
+String? _screenNameFor(RouteSettings settings) {
+  final name = settings.name;
+  if (name == null) return null;
+  return _screenNameByRoute[name]?.value;
+}
+
 GoRouter buildRouter(Ref ref) {
   final notifier = RouterNotifier(ref);
+  final analyticsObserver = FirebaseAnalyticsObserver(
+    analytics: FirebaseAnalytics.instance,
+    nameExtractor: _screenNameFor,
+  );
 
   return GoRouter(
     initialLocation: kThemePreviewEnabled ? '/_theme_preview' : '/splash',
     refreshListenable: notifier,
+    observers: [analyticsObserver],
     redirect: (context, state) {
       // Theme preview is dev-only and intentionally bypasses auth + onboarding
       // gates so it can be opened on any device build.