Phase 4 Stage 6: chat-room countdown UX + voice-call mode pill

Customer chat screen:
- Voice-call header pill (mode == 'call' renders accent-colored pill;
  chat mode renders no pill).
- HaloSnackbar fires once per session at 180s remaining ('sisa 3 menit
  lagi ya 🤍'), driven by the backend session_warning WS event.
- Last-2-min danger styling: timer pill flips to HaloTokens.danger +
  bold JetBrainsMono when remaining <= 120s.
- Floating ChatExpiredBanner widget injected above the input bar when
  remaining hits 0 in closing-grace state. perpanjang -> existing
  pricing bottom sheet.
- pricing_bottom_sheet.dart rewritten to the 5-option layout with
  chat|call mode toggle (mirrors duration-pick from Stage 3).

Mitra chat screen: voice-call header pill only (no countdown UX per PRD).

Backend:
- session.service.js getSessionById JOINs payment_sessions so mode +
  expires_at ship in /api/shared/chat/:id/info.
- session-timer.service.js onThreeMinuteWarning now emits expires_at +
  remaining_seconds for client resync.
- Dev-only POST /internal/_test/force-session-expires-at clears the
  3-min flag, reschedules the timer, and broadcasts WS resync. Lets
  the Maestro flow drive 175s -> 90s -> 0s without waiting live.

New chatRemainingSeconds StreamProvider derived from expiresAt, fed by
session_warning / session_timer / session_expired resync messages
(plan referenced a secondsLeftProvider that didn't actually exist).

Maestro 06_chat_countdown.yaml + force_session_expires_at.js helper.

Out of scope: meet.google.com URL launching - url_launcher isn't a
client_app dependency and message bubbles render plain Text. Defer.

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

backend/src/services/session-timer.service.js

@@ -12,6 +12,33 @@ const sql = getDb()
 // (e.g. extension reschedule). This matches the Phase 4 spec: "fire once".
 const sessionTimers = new Map()
 
+/**
+ * Dev/test-only — clear the per-session "3-min warning already fired" flag so
+ * the warning can fire again after `force-session-expires-at` reschedules a
+ * session backwards. Production code never needs this.
+ */
+export const _resetThreeMinFiredForTest = (sessionId) => {
+  const timers = sessionTimers.get(sessionId)
+  if (timers) timers.threeMinFired = false
+}
+
+/**
+ * Dev/test-only — push an immediate WS resync of the timer state so a Maestro
+ * flow can drive the customer UI through the danger pill / expired banner
+ * states without waiting for the next scheduled tick. Production code drives
+ * UX off the scheduled `session_timer` / `session_warning` / `session_expired`
+ * events instead.
+ */
+export const _broadcastTimerResyncForTest = (sessionId, expiresAt) => {
+  const remaining = Math.max(0, Math.floor((new Date(expiresAt).getTime() - Date.now()) / 1000))
+  sendToSessionParticipant(sessionId, UserType.CUSTOMER, {
+    type: WsMessage.SESSION_TIMER,
+    remaining_seconds: remaining,
+    expires_at: expiresAt,
+    session_id: sessionId,
+  })
+}
+
 export const startSessionTimer = (sessionId, expiresAt) => {
   const now = Date.now()
   const expiresMs = new Date(expiresAt).getTime()
@@ -89,15 +116,23 @@ const onSessionWarning = (sessionId) => {
 /**
  * Phase 4 — 3-min warning. Customer-only event (mitra has no countdown UI).
  * Idempotent per session via the `threeMinFired` flag captured by startSessionTimer.
+ *
+ * Includes `remaining_seconds` and `expires_at` so the client can resync its
+ * local ticker against the server's view of when the session ends. The
+ * customer-side ticker drives the last-2-min danger pill + expired banner,
+ * neither of which the server emits a discrete event for.
  */
-const onThreeMinuteWarning = (sessionId) => {
+const onThreeMinuteWarning = async (sessionId) => {
   const timers = sessionTimers.get(sessionId)
   if (timers?.threeMinFired) return // belt-and-braces — should not happen
   if (timers) timers.threeMinFired = true
+  const [row] = await sql`SELECT expires_at FROM chat_sessions WHERE id = ${sessionId}`
   sendToSessionParticipant(sessionId, UserType.CUSTOMER, {
     type: WsMessage.SESSION_WARNING,
     kind: 'three_minutes_left',
     session_id: sessionId,
+    remaining_seconds: 180,
+    expires_at: row?.expires_at ?? null,
   })
 }
 

backend/src/services/session.service.js

@@ -149,15 +149,20 @@ export const listSessions = async ({ page = 1, limit = 20, status, topic_sensiti
 }
 
 export const getSessionById = async (sessionId) => {
+  // `mode` lives on payment_sessions (chat | call), introduced in Phase 4.1.
+  // The chat header pill needs it, so surface it on every session.info read.
+  // Falls back to 'chat' for pre-3.7 rows where payment_session_id is null.
   const [session] = await sql`
     SELECT cs.id, cs.customer_id, cs.mitra_id, cs.status, cs.topic_sensitivity, cs.topics,
       cs.created_at, cs.paired_at, cs.ended_at, cs.ended_by,
       cs.duration_minutes, cs.price, cs.is_first_session_discount, cs.expires_at, cs.extended_minutes,
+      COALESCE(ps.mode, 'chat') AS mode,
       c.display_name AS customer_display_name,
       m.display_name AS mitra_display_name
     FROM chat_sessions cs
     INNER JOIN customers c ON c.id = cs.customer_id
     LEFT JOIN mitras m ON m.id = cs.mitra_id
+    LEFT JOIN payment_sessions ps ON ps.id = cs.payment_session_id
     WHERE cs.id = ${sessionId}
   `
   return session