Economy: free vs paid games + buy-coins page; friends remove confirmation

- Coins only matter for ranked: free games (vs computer / private friend rooms)
  cost nothing; random ranked requires an entry (stake), gated by balance →
  routes to buy-coins when short
- Buy Coins page (CoinPack/getCoinPacks/buyCoins; mock credits now, real
  Zarinpal/IDPay TODO); TopBar coins → buy; lobby create-room is Free
- Friends: removed instant red ✕ delete; UserMinus → inline confirm before remove

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

src/lib/online/mock-service.ts

@@ -21,6 +21,7 @@ import {
   AppNotification,
   AuthSession,
   ChatMessage,
+  CoinPack,
   Conversation,
   DailyRewardState,
   Friend,
@@ -772,6 +773,26 @@ export class MockOnlineService implements OnlineService {
 
   /* --------------------- leaderboard / shop / daily ------------------ */
 
+  async getCoinPacks(): Promise<CoinPack[]> {
+    return [
+      { id: "p1", coins: 1000, bonus: 0, priceToman: 19000 },
+      { id: "p2", coins: 5000, bonus: 500, priceToman: 89000, tag: "popular" },
+      { id: "p3", coins: 12000, bonus: 2000, priceToman: 179000, tag: "best" },
+      { id: "p4", coins: 30000, bonus: 7000, priceToman: 399000 },
+    ];
+  }
+
+  async buyCoins(packId: string) {
+    const p = await this.getProfile();
+    const pack = (await this.getCoinPacks()).find((x) => x.id === packId);
+    if (!pack) return { ok: false, coins: 0 };
+    // NOTE: real payment (Zarinpal/IDPay) goes here. For now we credit instantly.
+    const added = pack.coins + pack.bonus;
+    this.profile = { ...p, coins: p.coins + added };
+    this.saveProfile();
+    return { ok: true, profile: this.profile, coins: added };
+  }
+
   private onlineCount = 600 + Math.floor(Math.random() * 900);
   async getOnlineCount(): Promise<number> {
     // gentle random walk so the badge feels alive