Add friend chat; replace betting wording (شرط) with entry coins

- Friend-to-friend chat outside the game (ChatScreen) with mock replies,
  per-friend history, unread tracking; chat button on each friend row
- OnlineService + mock + online-store extended with chat (list/get/send/markRead)
- Reframe gambling term: "شرط"/"Stake" -> "سکه ورودی"/"Entry coins";
  free entry labeled رایگان/Free

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/online/mock-service.ts

@@ -12,6 +12,8 @@ import {
 import {
   AVATARS,
   AuthSession,
+  ChatMessage,
+  Conversation,
   DailyRewardState,
   Friend,
   FriendRequest,
@@ -52,8 +54,22 @@ const LS = {
   session: "hokm.session",
   profile: "hokm.profile",
   daily: "hokm.daily",
+  chats: "hokm.chats",
 };
 
+const CANNED_REPLIES = [
+  "سلام! 👋",
+  "بزن بریم 🔥",
+  "یه دست دیگه؟",
+  "من آماده‌ام",
+  "آفرین، کارت خوب بود",
+  "حکم چی بکنیم؟",
+  "😂😂",
+  "الان میام بازی",
+  "حتماً!",
+  "تو رو خدا این دفعه کُتمون نکن 😅",
+];
+
 function load<T>(key: string): T | null {
   if (!isBrowser()) return null;
   try {
@@ -132,14 +148,19 @@ export class MockOnlineService implements OnlineService {
   private currentOppRating = 1000;
   private lastOtp = "";
 
+  private messages: Record<string, ChatMessage[]> = {};
+  private unread: Record<string, number> = {};
+
   private roomCbs = new Set<(r: Room) => void>();
   private mmCbs = new Set<(s: MatchmakingState) => void>();
   private friendCbs = new Set<(f: Friend[]) => void>();
+  private chatCbs = new Set<(friendId: string, m: ChatMessage[]) => void>();
   private timers: ReturnType<typeof setTimeout>[] = [];
 
   constructor() {
     this.session = load<AuthSession>(LS.session);
     this.profile = load<UserProfile>(LS.profile);
+    this.messages = load<Record<string, ChatMessage[]>>(LS.chats) ?? {};
     this.seedFriends();
   }
 
@@ -320,6 +341,73 @@ export class MockOnlineService implements OnlineService {
     return () => this.friendCbs.delete(cb);
   }
 
+  /* ------------------------------- chat ------------------------------ */
+
+  private saveChats() {
+    save(LS.chats, this.messages);
+  }
+  private emitChat(friendId: string) {
+    const msgs = this.messages[friendId] ?? [];
+    for (const cb of this.chatCbs) cb(friendId, [...msgs]);
+  }
+
+  async listConversations(): Promise<Conversation[]> {
+    const convs: Conversation[] = [];
+    for (const friend of this.friends) {
+      const msgs = this.messages[friend.id];
+      if (!msgs || msgs.length === 0) continue;
+      convs.push({
+        friend,
+        lastMessage: msgs[msgs.length - 1],
+        unread: this.unread[friend.id] ?? 0,
+      });
+    }
+    return convs.sort(
+      (a, b) => (b.lastMessage?.ts ?? 0) - (a.lastMessage?.ts ?? 0)
+    );
+  }
+
+  async getMessages(friendId: string): Promise<ChatMessage[]> {
+    return [...(this.messages[friendId] ?? [])];
+  }
+
+  async sendMessage(friendId: string, text: string): Promise<ChatMessage> {
+    const msg: ChatMessage = {
+      id: rid("m"),
+      fromMe: true,
+      text: text.trim(),
+      ts: Date.now(),
+    };
+    this.messages[friendId] = [...(this.messages[friendId] ?? []), msg];
+    this.saveChats();
+    this.emitChat(friendId);
+
+    // simulate a reply from the friend
+    this.after(randInt(900, 1900), () => {
+      const reply: ChatMessage = {
+        id: rid("m"),
+        fromMe: false,
+        text: pick(CANNED_REPLIES),
+        ts: Date.now(),
+      };
+      this.messages[friendId] = [...(this.messages[friendId] ?? []), reply];
+      this.unread[friendId] = (this.unread[friendId] ?? 0) + 1;
+      this.saveChats();
+      this.emitChat(friendId);
+    });
+
+    return msg;
+  }
+
+  async markRead(friendId: string) {
+    this.unread[friendId] = 0;
+  }
+
+  onChat(cb: (friendId: string, m: ChatMessage[]) => void): Unsubscribe {
+    this.chatCbs.add(cb);
+    return () => this.chatCbs.delete(cb);
+  }
+
   /* ------------------------------ rooms ------------------------------ */
 
   private seatYou(): RoomSeat {

src/lib/online/service.ts

@@ -4,6 +4,8 @@
 
 import {
   AuthSession,
+  ChatMessage,
+  Conversation,
   DailyRewardState,
   Friend,
   FriendRequest,
@@ -53,6 +55,13 @@ export interface OnlineService {
   removeFriend(id: string): Promise<void>;
   onFriends(cb: (friends: Friend[]) => void): Unsubscribe;
 
+  /* ----- chat ----- */
+  listConversations(): Promise<Conversation[]>;
+  getMessages(friendId: string): Promise<ChatMessage[]>;
+  sendMessage(friendId: string, text: string): Promise<ChatMessage>;
+  markRead(friendId: string): Promise<void>;
+  onChat(cb: (friendId: string, messages: ChatMessage[]) => void): Unsubscribe;
+
   /* ----- rooms ----- */
   createRoom(opts: CreateRoomOptions): Promise<Room>;
   setPartner(roomId: string, friendId: string | null): Promise<Room>;

src/lib/online/types.ts

@@ -245,6 +245,21 @@ export interface DailyRewardState {
   available: boolean;
 }
 
+/* ------------------------------- Chat -------------------------------- */
+
+export interface ChatMessage {
+  id: string;
+  fromMe: boolean;
+  text: string;
+  ts: number;
+}
+
+export interface Conversation {
+  friend: Friend;
+  lastMessage: ChatMessage | null;
+  unread: number;
+}
+
 /* ------------------------------ Avatars ------------------------------ */
 
 export const AVATARS: { id: string; emoji: string }[] = [