rebuild the app on a typed, modular structure wired to the real API

The whole app lived in one 3,071-line App.tsx on a Figma scaffold (60 unused
packages, 45 unused UI components, no type-check). The live site could not
reach the backend, Persian-keyboard digits were erased from the phone field,
guests were signed out after an hour, "mark read" hit a method the server
does not accept (405), and iOS Safari blocked the payment window.

What changed:
- src/ split into api/ (one typed client: timeouts, GET retry, single-flight
  refresh, SSE), screens/ (one file each), components/, state/, nav/, lib/.
- The API address is configuration only: public/config.js at runtime, then
  VITE_API_BASE_URL at build time, then same-origin /api. No domain in code.
- Responsive shell instead of a fixed 390x844 phone frame; self-hosted
  Vazirmatn instead of Google Fonts; strict TypeScript, `npm run build`
  type-checks first.
- Everything on the handoff list: tutor answers keep their line breaks, have
  thumbs up/down, follow-ups, "from the book" badge, retry, history that
  survives tab switches and reloads, "why was I wrong" from a wrong answer
  with questionId; question reports; hearts with maxHearts/unlimited and a
  no-hearts screen with the refill time; result screen and a visible error
  when lesson completion fails; subscription status, badge, discount code
  before the gateway and the payment-return message; guest refresh token;
  6-digit OTP with resend timer; age saved as a Jalali birthYear; PATCH
  read-all; leaderboard refetched on open with "you" highlighted; selected
  companion shown across the app; logout that revokes the refresh token.
- New screens for endpoints that had none: profile, streak calendar,
  support tickets and bug reports, parents, invite-a-friend (with ?ref=
  tracking), guest-to-phone upgrade.
- Browser/phone back button walks the screen stack.

Checked with a headless-Chrome walkthrough against a local backend at
390x844 and 360x740 (fresh guest: onboarding, setup, a full lesson, map,
island sheet, every tab and sub-screen, one real tutor question, reload,
logout): no console errors, no failed API calls. Real SMS login and a real
Zarinpal payment were not exercised.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/state/askStore.ts

@@ -0,0 +1,86 @@
+import { useSyncExternalStore } from 'react';
+import type { UsedChunk } from '@/api';
+import { KEYS, store } from '@/lib/storage';
+
+/**
+ * گفتگوی دستیار، بیرون از کامپوننت تا با عوض کردنِ تب پاک نشود.
+ * شناسه‌ی گفتگو در localStorage می‌ماند و بعد از بستنِ اپ تاریخچه از سرور برمی‌گردد.
+ */
+export interface ChatMessage {
+  localId: number;
+  role: 'user' | 'assistant';
+  text: string;
+  messageId?: string;
+  usedChunks?: UsedChunk[];
+  followUps?: string[];
+  feedback?: 'up' | 'down';
+  /** پیامِ خطا به‌جای پاسخ؛ با «دوباره» همان سوال دوباره فرستاده می‌شود. */
+  failedQuestion?: string;
+}
+
+interface AskState {
+  messages: ChatMessage[];
+  conversationId: string | null;
+  /** درسی که گفتگو درباره‌ی آن است؛ عوض شدنش یعنی گفتگوی تازه. */
+  lessonId: number | null;
+  historyLoaded: boolean;
+}
+
+let state: AskState = {
+  messages: [],
+  conversationId: store.get(KEYS.conversationId),
+  lessonId: null,
+  historyLoaded: false,
+};
+let nextLocalId = 1;
+const listeners = new Set<() => void>();
+
+function emit(next: Partial<AskState>) {
+  state = { ...state, ...next };
+  if ('conversationId' in next) {
+    if (state.conversationId) store.set(KEYS.conversationId, state.conversationId);
+    else store.remove(KEYS.conversationId);
+  }
+  listeners.forEach((l) => l());
+}
+
+export const askStore = {
+  get: () => state,
+  subscribe(listener: () => void) {
+    listeners.add(listener);
+    return () => {
+      listeners.delete(listener);
+    };
+  },
+  add(message: Omit<ChatMessage, 'localId'>): number {
+    const localId = nextLocalId++;
+    emit({ messages: [...state.messages, { ...message, localId }] });
+    return localId;
+  },
+  update(localId: number, patch: Partial<ChatMessage>) {
+    emit({ messages: state.messages.map((m) => (m.localId === localId ? { ...m, ...patch } : m)) });
+  },
+  remove(localId: number) {
+    emit({ messages: state.messages.filter((m) => m.localId !== localId) });
+  },
+  setConversation(conversationId: string | null, lessonId: number | null = state.lessonId) {
+    emit({ conversationId, lessonId });
+  },
+  setHistory(messages: Omit<ChatMessage, 'localId'>[]) {
+    emit({ messages: messages.map((m) => ({ ...m, localId: nextLocalId++ })), historyLoaded: true });
+  },
+  markHistoryLoaded() {
+    emit({ historyLoaded: true });
+  },
+  reset(lessonId: number | null = null) {
+    emit({ messages: [], conversationId: null, lessonId, historyLoaded: true });
+  },
+  /** بعد از خروج از حساب، گفتگوی کاربرِ قبلی نباید بماند. */
+  clear() {
+    emit({ messages: [], conversationId: null, lessonId: null, historyLoaded: false });
+  },
+};
+
+export function useAskState(): AskState {
+  return useSyncExternalStore(askStore.subscribe, askStore.get);
+}