Phase 4 §1/§5: notif banner detection on API <33 + chat-delivery WS→FCM lifecycle

§1 notif banner: permission_handler v11 returns granted unconditionally
for Permission.notification on Android <13 because POST_NOTIFICATIONS
didn't exist as a runtime permission. Result: SHome1st amber "notifikasi
off" banner never showed on API 24-32 even when the user toggled
notifications off in Settings → Apps. Add a
NotificationManagerCompat.areNotificationsEnabled() pre-check via
flutter_local_notifications (works from API 19+) so the banner reflects
the real OS state on older Android.

§5 chat delivery: the contract is "WS when foreground, FCM when
background", but the previous build only honoured (1) — Android keeps
the TCP socket alive after the Dart isolate is paused, so backend's
`socket.readyState === 1` check returned true and FCM never fired.
Fix has five parts (all required together):

 1. Customer-side lifecycle observer in client_app/main.dart closes
    chatProvider's WS on paused/detached, reconnects on resumed.
 2. `_appPaused` gate in main.dart suppresses the activeSessionProvider
    listener's auto-reconnect (15s poll in active_session_notifier
    would otherwise re-open the WS the next tick after the observer
    closed it — defeating the fallback).
 3. Mitra-side lifecycle observer in mitra_app/main.dart stashes
    `_pausedChatSessionId`, calls mitraChatProvider.disconnect(), and
    re-issues connect(saved) on resumed.
 4. MitraChat gains a `_connectedSessionId` field + getter so the
    observer in step 3 can read it back across disconnect (disconnect
    clears it; the next connect overwrites it).
 5. SearchingScreen resets pairingProvider when entering with a new
    draft.paymentId — previously it retained PairingActiveData with
    the *old* sessionId after a session ended, and the next pairing
    flow navigated straight to that completed session showing
    "Sesi sudah berakhir".

Backend additions under /internal/_test/* for assertion harness:
inspectSessionWsState + GET /ws-connection-state,
POST /send-chat-message-as-mitra (with delivered_via),
POST /send-chat-message-as-customer (with delivered_via),
POST /send-fcm-chat-message (raw FCM dispatch).

Maestro coverage:
 - ts-customer-05-01: mitra → customer message when customer is
   backgrounded → delivered_via=fcm.
 - ts-customer-05-02: customer → mitra message when mitra is
   backgrounded → delivered_via=fcm.
 - ts-customer-01-01: §1 notif-denied banner on home. Documented
   precondition: mitra must be force-stopped or backgrounded on the
   chat screen before 05-02 runs (Maestro can only drive one --udid
   per run; mitra-side lifecycle observer end-to-end is deferred).

Helper scripts under client_app/.maestro/scripts/:
inspect_ws_state.js, assert_ws_state.js,
send_chat_message_as_mitra.js, assert_delivered_via.js (takes
SENDER=mitra|customer to route to the matching backend endpoint).

README_section_05.md documents the test plan, helper scripts, and the
deferred mitra-side maestro driving. Both apps tested manually on
API 28 AVDs where FCM delivery is sub-second; API 24 has 5-30 min
heartbeats that make it impractical for FCM-related testing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

client_app/.maestro/flows/README_section_05.md

@@ -0,0 +1,93 @@
+# §5 — Chat Room test plan
+
+Spec: [requirement/flow_customer.mermaid.md §5](../../../requirement/flow_customer.mermaid.md)
+plus the user-stated message-delivery contract:
+
+> 1. WebSocket when app is foreground / WS connected.
+> 2. FCM when app is background / WS disconnected.
+
+The lifecycle observers that enforce (2) live at:
+- Customer side: `client_app/lib/main.dart::_AppState.didChangeAppLifecycleState`
+- Mitra side: `mitra_app/lib/main.dart::_AppState.didChangeAppLifecycleState` +
+  `mitra_app/lib/core/chat/mitra_chat_notifier.dart` (`_connectedSessionId`
+  + getter for the observer to read on `paused`).
+
+A 15s `Timer.periodic` in `active_session_notifier.dart` would otherwise
+re-open the customer WS right after the observer closed it; the
+`_appPaused` gate in customer main.dart suppresses that race.
+
+## Implemented
+
+| File | Direction | Expected dispatch |
+|---|---|---|
+| `ts-customer-05-01-background_disconnects_ws_so_messages_fall_back_to_fcm.yaml` | mitra → customer, customer is backgrounded | `delivered_via=fcm` |
+| `ts-customer-05-02-customer_message_to_backgrounded_mitra_falls_back_to_fcm.yaml` | customer → mitra, mitra is backgrounded | `delivered_via=fcm` |
+
+Both flows drive the customer device only (Maestro can only target one
+`--udid` per run). The mitra side is verified server-side via
+[`/internal/_test/ws-connection-state`](../../../backend/src/routes/internal/_test.routes.js)
+and
+[`/internal/_test/send-chat-message-as-customer`](../../../backend/src/routes/internal/_test.routes.js)
+(introduced 2026-05-18 with the lifecycle fix).
+
+## Helper scripts (under `../scripts/`)
+
+| Script | Purpose |
+|---|---|
+| `assert_ws_state.js` | Reads `/internal/_test/ws-connection-state?session_id=…`; throws on mismatch with `EXPECTED_CUSTOMER_CONNECTED` / `EXPECTED_MITRA_CONNECTED`. |
+| `assert_delivered_via.js` | Sends a chat message via the test endpoint matching `SENDER` (`mitra` default, or `customer`); asserts the response's `delivered_via` equals `EXPECTED_DELIVERED_VIA`. |
+| `inspect_ws_state.js` | Same data as `assert_ws_state.js` but exports the booleans into `output.CUSTOMER_CONNECTED` / `output.MITRA_CONNECTED` for downstream conditions without throwing. |
+| `send_chat_message_as_mitra.js` | Mitra→customer one-shot send. Captures `output.MESSAGE_ID` + `output.DELIVERED_VIA`. |
+
+## Pre-reqs for both flows
+
+- Backend reachable; `NODE_ENV != 'production'`.
+- ≥1 mitra online (the `seed_history_session.js` helper picks the
+  most-recently-online mitra to act as the eventual acceptor).
+- For 05-01: customer device is the one Maestro drives; `pressKey: HOME`
+  inside the flow backgrounds it. No mitra-app interaction required.
+- For 05-02: **the mitra app on `emulator-5556` must be backgrounded or
+  force-stopped before the flow runs**. The `assert_ws_state.js` guard
+  fails loudly if mitra is foreground (proving WS-over-FCM precedence —
+  also a correct test outcome, just the wrong side of the matrix). To
+  ensure FCM actually arrives on the device, the mitra account on
+  `emulator-5556` must have a `fcm_token` in `mitras.fcm_token` (i.e.,
+  the app has signed in and called `/api/shared/device-token` at some
+  point) — verified by `seed_history_session.js`'s output mitra ID and
+  the `MITRA_NAME_RE` it captures.
+
+## Manual mitra-side verification
+
+After 05-02 passes, optionally inspect the mitra device's notification
+shade to confirm the FCM tray notification rendered:
+
+```bash
+export ADB_SERVER_SOCKET=tcp:172.22.240.1:5037
+adb -s emulator-5556 shell cmd statusbar expand-notifications
+adb -s emulator-5556 exec-out screencap -p > /tmp/mitra_shade.png
+adb -s emulator-5556 shell cmd statusbar collapse
+```
+
+Expect to see a `Pesan baru dari Customer` notification within ~1s on an
+API 28+ AVD (older AVDs queue FCM for 5-30 min — see the per-AVD
+Play-Services notes in the project memory).
+
+## Not yet automated
+
+**Mitra-side lifecycle observer** end-to-end. To verify that the mitra
+app's `didChangeAppLifecycleState(paused)` actually closes its chat WS,
+the test would need to drive the mitra emulator (Maestro on
+`--udid emulator-5556`) through login → chat-screen → `pressKey: HOME` →
+assert backend WS state. This requires:
+
+1. Pre-seeding an active chat session for the currently-signed-in mitra
+   (no existing test endpoint for "seed customer + pair + active
+   session"; the existing scripts assume the customer app drives it).
+2. Driving the mitra OTP login + chat-request acceptance UI from
+   Maestro.
+
+Both are feasible but out of scope for the current iteration. The
+mitra-side fix is covered indirectly: ts-customer-05-02 asserts the
+backend correctly dispatches via FCM whenever the mitra WS is closed,
+and the mitra app's lifecycle observer was verified manually
+(2026-05-18) to be the mechanism that closes that WS.

client_app/.maestro/flows/ts-customer-01-01-notif_denied_shows_home_banner.yaml

@@ -0,0 +1,61 @@
+# ts-customer-01-01 — When OS-level notification permission is denied,
+# SHome1st renders the amber "notifikasi off" banner above the
+# 'aku mau curhat' CTA.
+# Spec ref: requirement/flow_customer.mermaid.md §1 — `NotifCheck → no →
+# HomeBanner` (line 24-26 of the mermaid).
+#
+# Banner widget: home_screen.dart::_NotifDeniedBanner. Gating provider:
+# notifPermissionStatusProvider (core/notifications/notif_permission.dart).
+# The provider reads `permission_handler::Permission.notification.status`
+# which, on Android 13+, reflects the runtime POST_NOTIFICATIONS state and
+# on older Android reflects the app's notification-enabled toggle.
+#
+# Pre-requisite (manual setup):
+#   The test only exercises the "denied" branch. Disable notifications for
+#   the customer app BEFORE invoking maestro:
+#     - Android 13+: maestro's `permissions: { notifications: deny }` below
+#       handles this (POST_NOTIFICATIONS is a runtime permission).
+#     - Android 7-12 (incl. the API-24 dev AVD): the runtime permission
+#       doesn't exist, so the maestro `permissions:` block is a no-op.
+#       Instead, toggle Settings → Apps → Halo Bestie → Notifications →
+#       Off manually. This sets the system `NotificationManagerCompat`
+#       state which the app's `notif_permission.dart::readStatus`
+#       pre-check picks up. `clearState: true` below is safe — `pm clear`
+#       wipes app data but not the system-level notification toggle.
+#   The backend FCM path still fires regardless of this branch (the OS
+#   simply suppresses the notification); the banner is the only
+#   user-visible signal that they're missing alerts, which is what we
+#   assert below.
+appId: com.halobestie.client.client_app
+env:
+  TEST_PHONE: "+6281234567890"
+  BACKEND_INTERNAL_URL: http://localhost:3001
+---
+- runScript:
+    file: ../scripts/reset_phone.js
+    env:
+      TEST_PHONE: ${TEST_PHONE}
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+- launchApp:
+    clearState: true
+    permissions:
+      notifications: deny
+- extendedWaitUntil:
+    visible:
+      text: "Mulai"
+    timeout: 15000
+- tapOn:
+    text: "Mulai"
+    retryTapIfNoChange: true
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*aku mau curhat.*"
+    timeout: 30000
+
+# §1 NotifCheck=no → SHome1st banner. Text is the unique copy from
+# _NotifDeniedBanner; the icon is decorative-only and not part of the
+# a11y label.
+- assertVisible: "(?s).*notifikasi off.*"
+- assertVisible: "(?s).*kelewat chat dari bestie.*"
+- assertVisible: "(?s).*nyalain.*"
+- takeScreenshot: /tmp/notif_banner_design

client_app/.maestro/flows/ts-customer-05-01-background_disconnects_ws_so_messages_fall_back_to_fcm.yaml

@@ -0,0 +1,151 @@
+# ts-customer-05-01 — When the customer app is backgrounded, the chat
+# WebSocket must close so backend `sendMessage` falls back to FCM.
+#
+# Spec ref: requirement/flow_customer.mermaid.md §5 (Chat Room) +
+# user-stated path:
+#   1. WebSocket when app is foreground / WS connected.
+#   2. FCM when app is background / WS disconnected.
+#
+# Fix under test: client_app/lib/main.dart `_AppState.didChangeAppLifecycleState`
+# closes the chat WS on AppLifecycleState.paused / detached. Before the
+# fix, Android kept the TCP socket alive after the Dart isolate paused, so
+# backend's `socket.readyState === 1` check returned true and FCM never
+# fired — the customer received no alert in background.
+#
+# Verification approach:
+#   1. Drive customer through pairing → active chat (same harness as
+#      ts-customer-04-04).
+#   2. Assert customer-side WS is connected (backend state check).
+#   3. Press HOME to background → wait briefly for the lifecycle observer
+#      to fire `disconnect()` and the socket-close to round-trip.
+#   4. Assert customer-side WS is now closed.
+#   5. Send a message AS mitra via the real `sendMessage` code path and
+#      assert it was delivered via FCM (recipient.customer WS was down at
+#      dispatch time).
+#
+# Pre-reqs:
+#   - Backend reachable; NODE_ENV != 'production'.
+#   - ≥1 mitra online (the seeded mitra acts as the blast acceptor and the
+#     subsequent message sender).
+appId: com.halobestie.client.client_app
+env:
+  TEST_PHONE: "+6281234567890"
+  BACKEND_INTERNAL_URL: http://localhost:3001
+---
+# ── Setup: pair customer with a mitra, land in active chat ──────────────
+- runScript:
+    file: ../scripts/reset_phone.js
+    env:
+      TEST_PHONE: ${TEST_PHONE}
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+- launchApp:
+    clearState: true
+- runFlow: ../subflows/onboarding_returning_user.yaml
+
+# Seed history so the SHomeReturning view renders the choice sheet (the
+# seeded mitra also becomes the blast acceptor).
+- runScript:
+    file: ../scripts/seed_history_session.js
+    env:
+      TEST_PHONE: ${TEST_PHONE}
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+- swipe:
+    start: "50%, 30%"
+    end: "50%, 80%"
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*curhatan sebelumnya.*"
+    timeout: 10000
+
+# "curhat sama bestie baru" → choice sheet → "bestie baru" → method-pick
+- tapOn:
+    text: "(?s).*curhat sama bestie baru.*"
+    retryTapIfNoChange: true
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*mau curhat sama siapa.*"
+    timeout: 5000
+- tapOn: "(?s).*cari bestie baru yang siap dengerin.*"
+
+# Payment chain → confirm → pairing accepted.
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*pilih cara curhat.*"
+    timeout: 10000
+- tapOn:
+    text: "(?s).*tulis dan baca dengan tenang.*"
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*pilih durasi.*"
+    timeout: 10000
+- tapOn: "(?s).*5 menit.*"
+- tapOn: "(?s).*bayar Rp.*"
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*cara bayar.*"
+    timeout: 10000
+- tapOn:
+    text: "(?s).*bayar Rp.*"
+    retryTapIfNoChange: true
+- extendedWaitUntil:
+    visible:
+      text: "scan QRIS untuk bayar"
+    timeout: 10000
+- runScript:
+    file: ../scripts/mark_latest_payment_paid.js
+    env:
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+- runFlow:
+    when:
+      visible:
+        text: "(?s).*biar nggak ketinggalan.*"
+    commands:
+      - tapOn:
+          text: "(?s).*nanti aja.*"
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*lagi nyari bestie.*"
+    timeout: 20000
+- runScript:
+    file: ../scripts/mitra_accept_latest_internal.js
+    env:
+      MITRA_ID: ${output.MITRA_ID}
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*online.*"
+    timeout: 20000
+
+# ── Assertion 1: WS is connected when chat screen is in foreground ──────
+- runScript:
+    file: ../scripts/assert_ws_state.js
+    env:
+      SESSION_ID: ${output.ACCEPTED_SESSION_ID}
+      EXPECTED_CUSTOMER_CONNECTED: "true"
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+
+# ── Background the app: customer's WS should close ──────────────────────
+- pressKey: HOME
+
+# Give the lifecycle observer + socket-close round-trip a moment. The
+# disconnect() call posts a close frame; the backend reacts on
+# `socket.on('close')`. ~1s is usually sufficient on the dev backend.
+- waitForAnimationToEnd:
+    timeout: 3000
+
+# ── Assertion 2: backend now reports customer_connected=false ───────────
+- runScript:
+    file: ../scripts/assert_ws_state.js
+    env:
+      SESSION_ID: ${output.ACCEPTED_SESSION_ID}
+      EXPECTED_CUSTOMER_CONNECTED: "false"
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+
+# ── Assertion 3: a message sent now is delivered via FCM, not WebSocket ─
+- runScript:
+    file: ../scripts/assert_delivered_via.js
+    env:
+      SESSION_ID: ${output.ACCEPTED_SESSION_ID}
+      CONTENT: "halo, balasan dari mitra sementara kamu di background"
+      EXPECTED_DELIVERED_VIA: "fcm"
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}

client_app/.maestro/flows/ts-customer-05-02-customer_message_to_backgrounded_mitra_falls_back_to_fcm.yaml

@@ -0,0 +1,144 @@
+# ts-customer-05-02 — Symmetric to 05-01: customer sends a message and the
+# mitra is in background → backend `sendMessage` falls back to FCM.
+#
+# Spec ref: requirement/flow_customer.mermaid.md §5 (Chat Room) +
+# the user-stated path:
+#   1. WebSocket when app is foreground / WS connected.
+#   2. FCM when app is background / WS disconnected.
+#
+# Fix under test: mitra_app/lib/main.dart `_AppState.didChangeAppLifecycleState`
+# closes the chat WS on paused/detached (and `mitra_chat_notifier.dart`
+# exposes `connectedSessionId` + clears it on disconnect). Without this,
+# Android keeps the TCP socket alive after the Dart isolate pauses, so
+# the backend believes the mitra is online and never fires FCM — the
+# mitra misses customer messages while the app is in background.
+#
+# Approach (Maestro can only drive one device per flow; here we drive the
+# customer, and the mitra side is verified server-side):
+#   1. Drive customer to active chat (same harness as ts-customer-04-04 /
+#      ts-customer-05-01). The acceptor is whichever mitra the
+#      seed_history_session.js helper picks (most-recently-online → on
+#      our setup that is the signed-in mitra on emulator-5556).
+#   2. Assert backend says mitra_connected=false. This is true when:
+#        (a) the mitra app is force-stopped / not running, OR
+#        (b) the mitra app is on the chat screen AND backgrounded — the
+#            lifecycle observer should have closed the WS.
+#      Either condition fulfils the precondition for FCM fallback.
+#   3. Send a message AS customer via /internal/_test/send-chat-message-as-customer
+#      and assert delivered_via="fcm".
+#
+# Pre-reqs (HARD):
+#   - Backend reachable; NODE_ENV != 'production'.
+#   - emulator-5556 mitra app: either force-stopped before the test, or
+#     signed in with TestMitra-1501 (the seed_history_session pick) and
+#     currently backgrounded. If the mitra is foreground in the chat
+#     screen, mitra_connected=true and this test asserts will fail —
+#     which is the correct failure mode (proves WS-over-FCM precedence).
+#   - The currently-signed-in mitra must have a `fcm_token` row in
+#     `mitras.fcm_token`; otherwise the FCM dispatch succeeds at the
+#     backend code path but never reaches a device.
+appId: com.halobestie.client.client_app
+env:
+  TEST_PHONE: "+6281234567890"
+  BACKEND_INTERNAL_URL: http://localhost:3001
+---
+# ── Setup: drive customer through onboarding → pair via blast ───────────
+- runScript:
+    file: ../scripts/reset_phone.js
+    env:
+      TEST_PHONE: ${TEST_PHONE}
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+- launchApp:
+    clearState: true
+- runFlow: ../subflows/onboarding_returning_user.yaml
+
+- runScript:
+    file: ../scripts/seed_history_session.js
+    env:
+      TEST_PHONE: ${TEST_PHONE}
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+- swipe:
+    start: "50%, 30%"
+    end: "50%, 80%"
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*curhatan sebelumnya.*"
+    timeout: 10000
+
+- tapOn:
+    text: "(?s).*curhat sama bestie baru.*"
+    retryTapIfNoChange: true
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*mau curhat sama siapa.*"
+    timeout: 5000
+- tapOn: "(?s).*cari bestie baru yang siap dengerin.*"
+
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*pilih cara curhat.*"
+    timeout: 10000
+- tapOn:
+    text: "(?s).*tulis dan baca dengan tenang.*"
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*pilih durasi.*"
+    timeout: 10000
+- tapOn: "(?s).*5 menit.*"
+- tapOn: "(?s).*bayar Rp.*"
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*cara bayar.*"
+    timeout: 10000
+- tapOn:
+    text: "(?s).*bayar Rp.*"
+    retryTapIfNoChange: true
+- extendedWaitUntil:
+    visible:
+      text: "scan QRIS untuk bayar"
+    timeout: 10000
+- runScript:
+    file: ../scripts/mark_latest_payment_paid.js
+    env:
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+- runFlow:
+    when:
+      visible:
+        text: "(?s).*biar nggak ketinggalan.*"
+    commands:
+      - tapOn:
+          text: "(?s).*nanti aja.*"
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*lagi nyari bestie.*"
+    timeout: 20000
+- runScript:
+    file: ../scripts/mitra_accept_latest_internal.js
+    env:
+      MITRA_ID: ${output.MITRA_ID}
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+- extendedWaitUntil:
+    visible:
+      text: "(?s).*online.*"
+    timeout: 20000
+
+# ── Assertion 1: backend says mitra is NOT connected ────────────────────
+# Precondition guard: if the mitra app is foreground, this assert fails
+# loud — which is what we want (it proves WS would win over FCM).
+- runScript:
+    file: ../scripts/assert_ws_state.js
+    env:
+      SESSION_ID: ${output.ACCEPTED_SESSION_ID}
+      EXPECTED_CUSTOMER_CONNECTED: "true"
+      EXPECTED_MITRA_CONNECTED: "false"
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}
+
+# ── Assertion 2: a customer-sent message is delivered via FCM ───────────
+- runScript:
+    file: ../scripts/assert_delivered_via.js
+    env:
+      SESSION_ID: ${output.ACCEPTED_SESSION_ID}
+      CONTENT: "halo bestie, ini pesan saat kamu di background"
+      EXPECTED_DELIVERED_VIA: "fcm"
+      SENDER: "customer"
+      BACKEND_INTERNAL_URL: ${BACKEND_INTERNAL_URL}

client_app/.maestro/scripts/assert_delivered_via.js

@@ -0,0 +1,40 @@
+// Send a chat message AS the given side and assert the delivery transport
+// matches EXPECTED_DELIVERED_VIA. Throws on mismatch.
+//
+// Env:
+//   SESSION_ID                (required)
+//   CONTENT                   (required)
+//   EXPECTED_DELIVERED_VIA    (required, "websocket" or "fcm")
+//   SENDER                    (optional, "mitra" (default) or "customer")
+//   BACKEND_INTERNAL_URL      (optional)
+const sessionId = SESSION_ID
+const content = CONTENT
+const expected = EXPECTED_DELIVERED_VIA
+const sender = typeof SENDER !== 'undefined' && SENDER ? SENDER : 'mitra'
+const url = BACKEND_INTERNAL_URL || 'http://localhost:3001'
+if (!sessionId) throw new Error('SESSION_ID env not set')
+if (!content) throw new Error('CONTENT env not set')
+if (expected !== 'websocket' && expected !== 'fcm') {
+  throw new Error('EXPECTED_DELIVERED_VIA must be "websocket" or "fcm"')
+}
+if (sender !== 'mitra' && sender !== 'customer') {
+  throw new Error('SENDER must be "mitra" or "customer"')
+}
+
+const endpoint =
+  sender === 'mitra'
+    ? '/internal/_test/send-chat-message-as-mitra'
+    : '/internal/_test/send-chat-message-as-customer'
+const resp = http.post(`${url}${endpoint}`, {
+  headers: { 'Content-Type': 'application/json' },
+  body: JSON.stringify({ session_id: sessionId, content }),
+})
+if (resp.status !== 200) {
+  throw new Error(`send-chat-message-as-mitra failed (${resp.status}): ${resp.body}`)
+}
+const data = json(resp.body)
+if (data.delivered_via !== expected) {
+  throw new Error(`delivered_via mismatch: expected=${expected}, got=${data.delivered_via}`)
+}
+output.MESSAGE_ID = data.message_id
+output.DELIVERED_VIA = data.delivered_via

client_app/.maestro/scripts/assert_ws_state.js

@@ -0,0 +1,35 @@
+// Assert backend's in-memory WS connection state for a session matches
+// expectations. Throws (fails the maestro flow) on mismatch.
+//
+// Env:
+//   SESSION_ID                       (required)
+//   EXPECTED_CUSTOMER_CONNECTED      (required, "true" or "false")
+//   EXPECTED_MITRA_CONNECTED         (optional, "true" or "false")
+//   BACKEND_INTERNAL_URL             (optional, default http://localhost:3001)
+const sessionId = SESSION_ID
+const expCust = EXPECTED_CUSTOMER_CONNECTED
+const expMitra = typeof EXPECTED_MITRA_CONNECTED !== 'undefined' ? EXPECTED_MITRA_CONNECTED : null
+const url = BACKEND_INTERNAL_URL || 'http://localhost:3001'
+if (!sessionId) throw new Error('SESSION_ID env not set')
+if (expCust !== 'true' && expCust !== 'false') {
+  throw new Error('EXPECTED_CUSTOMER_CONNECTED must be "true" or "false"')
+}
+
+const resp = http.get(`${url}/internal/_test/ws-connection-state?session_id=${sessionId}`)
+if (resp.status !== 200) {
+  throw new Error(`ws-connection-state failed (${resp.status}): ${resp.body}`)
+}
+const data = json(resp.body)
+
+const gotCust = String(data.customer_connected)
+if (gotCust !== expCust) {
+  throw new Error(`customer_connected mismatch: expected=${expCust}, got=${gotCust}`)
+}
+if (expMitra !== null) {
+  const gotMitra = String(data.mitra_connected)
+  if (gotMitra !== expMitra) {
+    throw new Error(`mitra_connected mismatch: expected=${expMitra}, got=${gotMitra}`)
+  }
+}
+output.CUSTOMER_CONNECTED = gotCust
+output.MITRA_CONNECTED = String(data.mitra_connected)

client_app/.maestro/scripts/inspect_ws_state.js

@@ -0,0 +1,19 @@
+// Reads the in-memory websocket connection state for a given session via
+// the dev-only /internal/_test/ws-connection-state endpoint. Used to assert
+// that backgrounding the customer app closes its WS — the gate that flips
+// chat.service.sendMessage to the FCM fallback path.
+//
+// Env:
+//   SESSION_ID            (required)
+//   BACKEND_INTERNAL_URL  (optional, default http://localhost:3001)
+const sessionId = SESSION_ID
+const url = BACKEND_INTERNAL_URL || 'http://localhost:3001'
+if (!sessionId) throw new Error('SESSION_ID env not set')
+
+const resp = http.get(`${url}/internal/_test/ws-connection-state?session_id=${sessionId}`)
+if (resp.status !== 200) {
+  throw new Error(`ws-connection-state failed (${resp.status}): ${resp.body}`)
+}
+const data = json(resp.body)
+output.CUSTOMER_CONNECTED = String(data.customer_connected)
+output.MITRA_CONNECTED = String(data.mitra_connected)

client_app/.maestro/scripts/send_chat_message_as_mitra.js

@@ -0,0 +1,26 @@
+// Send a chat message AS the mitra of the given session via the dev-only
+// /internal/_test/send-chat-message-as-mitra endpoint. Goes through the
+// real chat.service.sendMessage code path. Returns which transport
+// carried the message — `websocket` if the customer's WS was alive at
+// dispatch time, `fcm` otherwise.
+//
+// Env:
+//   SESSION_ID            (required)
+//   CONTENT               (required, message body)
+//   BACKEND_INTERNAL_URL  (optional, default http://localhost:3001)
+const sessionId = SESSION_ID
+const content = CONTENT
+const url = BACKEND_INTERNAL_URL || 'http://localhost:3001'
+if (!sessionId) throw new Error('SESSION_ID env not set')
+if (!content) throw new Error('CONTENT env not set')
+
+const resp = http.post(`${url}/internal/_test/send-chat-message-as-mitra`, {
+  headers: { 'Content-Type': 'application/json' },
+  body: JSON.stringify({ session_id: sessionId, content }),
+})
+if (resp.status !== 200) {
+  throw new Error(`send-chat-message-as-mitra failed (${resp.status}): ${resp.body}`)
+}
+const data = json(resp.body)
+output.MESSAGE_ID = data.message_id
+output.DELIVERED_VIA = data.delivered_via

client_app/lib/core/notifications/notif_permission.dart

@@ -1,7 +1,9 @@
 import 'dart:async';
+import 'dart:io' show Platform;
 
 import 'package:firebase_messaging/firebase_messaging.dart';
 import 'package:flutter/widgets.dart';
+import 'package:flutter_local_notifications/flutter_local_notifications.dart';
 import 'package:permission_handler/permission_handler.dart' as ph;
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 
@@ -14,11 +16,29 @@ enum NotifPermStatus { notDetermined, granted, denied }
 ///   - iOS uses Firebase Messaging (which surfaces the system UNNotification
 ///     authorization status).
 ///   - Android 13+ uses `permission_handler` for `Permission.notification`
-///     (POST_NOTIFICATIONS runtime). Older Android always reports granted.
+///     (POST_NOTIFICATIONS runtime).
+///   - Android <13: POST_NOTIFICATIONS doesn't exist as a runtime permission,
+///     so `permission_handler` returns `granted` regardless of the user's
+///     Settings → Apps → Notifications toggle. We add a
+///     `NotificationManagerCompat.areNotificationsEnabled()` pre-check via
+///     `flutter_local_notifications` to honour that user-facing toggle on
+///     older Android.
 class NotifPermission {
   const NotifPermission();
 
   Future<NotifPermStatus> readStatus() async {
+    // Older Android: permission_handler can't see the
+    // Settings → Apps → Notifications toggle, so we ask the local-notifs
+    // plugin (backed by NotificationManagerCompat.areNotificationsEnabled,
+    // which works from API 19). If disabled there, surface it as `denied`
+    // so the SHome1st banner reflects reality on API 24-32.
+    if (Platform.isAndroid) {
+      final androidImpl = FlutterLocalNotificationsPlugin()
+          .resolvePlatformSpecificImplementation<
+              AndroidFlutterLocalNotificationsPlugin>();
+      final enabled = await androidImpl?.areNotificationsEnabled();
+      if (enabled == false) return NotifPermStatus.denied;
+    }
     final phStatus = await ph.Permission.notification.status;
     return _mapPh(phStatus);
   }

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

@@ -50,9 +50,22 @@ class _SearchingScreenState extends ConsumerState<SearchingScreen> {
       // "Curhat lagi" flow stamped the targeted mitra onto the draft before
       // payment, so we fire the targeted request and bounce to the dedicated
       // wait overlay; everything else is a general blast.
-      final state = ref.read(pairingProvider);
+      //
+      // Carry-over guard: if a previous chat session ended, pairingProvider
+      // retains its terminal state (PairingActiveData with the *old*
+      // sessionId, PairingFailed, PairingCancelled, etc). Without resetting
+      // here, the `state is PairingInitialData` branch wouldn't fire and
+      // `_onPairingState` below would re-emit a stale PairingActiveData →
+      // /chat/session/<old_sessionId>, dropping the customer on a chat
+      // screen for a `completed` session ("Sesi sudah berakhir"). Reset to
+      // Initial whenever we have a fresh payment to consume.
+      final draft = ref.read(paymentDraftNotifierProvider);
+      var state = ref.read(pairingProvider);
+      if (state is! PairingInitialData && draft.paymentId != null) {
+        ref.read(pairingProvider.notifier).reset();
+        state = ref.read(pairingProvider);
+      }
       if (state is PairingInitialData) {
-        final draft = ref.read(paymentDraftNotifierProvider);
         if (draft.paymentId != null) {
           if (draft.targetedMitraId != null) {
             // ignore: discarded_futures

client_app/lib/main.dart

@@ -40,13 +40,22 @@ class App extends ConsumerStatefulWidget {
   ConsumerState<App> createState() => _AppState();
 }
 
-class _AppState extends ConsumerState<App> {
+class _AppState extends ConsumerState<App> with WidgetsBindingObserver {
   bool _fcmRegistered = false;
   bool _authProvidersPreloaded = false;
+  // Tracks whether the OS has paused/detached this isolate. The
+  // activeSessionProvider runs a 15s poll (see active_session_notifier.dart);
+  // each tick fires the listener below, which would otherwise re-open the
+  // chat WebSocket immediately after didChangeAppLifecycleState closed it
+  // — defeating the WS→FCM fallback. We gate the reconnect on this flag so
+  // the WS stays closed while the app is backgrounded, even as polling
+  // continues.
+  bool _appPaused = false;
 
   @override
   void initState() {
     super.initState();
+    WidgetsBinding.instance.addObserver(this);
     // Phase 4: preload server-driven auth-provider gating once on cold start.
     // Cached via @Riverpod(keepAlive: true) — subsequent reads are instant.
     WidgetsBinding.instance.addPostFrameCallback((_) {
@@ -56,6 +65,45 @@ class _AppState extends ConsumerState<App> {
     });
   }
 
+  @override
+  void dispose() {
+    WidgetsBinding.instance.removeObserver(this);
+    super.dispose();
+  }
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    // Background → close the chat WebSocket so backend `sendMessage` falls
+    // back to FCM (chat.service.js:51 — `if (!delivered) sendPushNotification`).
+    // Without this, Android keeps the TCP socket alive after the Dart
+    // isolate is paused, so the backend believes the customer is online and
+    // never fires the push — the user sees no alert until they reopen the
+    // app. See flow_customer.mermaid.md §5 (chat room) and the
+    // implementation note in main.dart's activeSession listener.
+    //
+    // Foreground → re-establish the WS for the current active session, if
+    // any. activeSessionProvider's last cached snapshot drives the target
+    // session id; the chat notifier's `connectIfNotConnected` is a no-op
+    // when the same session is already wired up.
+    final notifier = ref.read(chatProvider.notifier);
+    if (state == AppLifecycleState.paused ||
+        state == AppLifecycleState.detached) {
+      _appPaused = true;
+      if (notifier.connectedSessionId != null) {
+        notifier.disconnect();
+      }
+    } else if (state == AppLifecycleState.resumed) {
+      _appPaused = false;
+      final snapshot = ref.read(activeSessionProvider).valueOrNull;
+      final sessionId = snapshot?.sessionId;
+      if (sessionId != null &&
+          (snapshot?.hasSession ?? false) &&
+          notifier.connectedSessionId != sessionId) {
+        notifier.connectIfNotConnected(sessionId);
+      }
+    }
+  }
+
   void _registerFcmToken() {
     if (_fcmRegistered) return;
     _fcmRegistered = true;
@@ -88,6 +136,12 @@ class _AppState extends ConsumerState<App> {
     // active session, regardless of which screen is mounted. The chat screen
     // only joins this connection — it doesn't own it. FCM remains the
     // background-only fallback.
+    //
+    // Gate on `_appPaused`: activeSessionProvider runs a 15s poll that fires
+    // this listener on every tick. If we reconnect while the app is
+    // backgrounded, we undo the disconnect that didChangeAppLifecycleState
+    // just performed and the FCM fallback never triggers for messages that
+    // arrive during background.
     ref.listen(activeSessionProvider, (prev, next) {
       final snapshot = next.valueOrNull;
       final notifier = ref.read(chatProvider.notifier);
@@ -97,6 +151,7 @@ class _AppState extends ConsumerState<App> {
         }
         return;
       }
+      if (_appPaused) return;
       final sessionId = snapshot.sessionId;
       if (sessionId != null && notifier.connectedSessionId != sessionId) {
         notifier.connectIfNotConnected(sessionId);