Achievements overhaul: 37 achievements, page with tabs, leagues, gating

Achievements (client + server mirror, metric-driven so the list is one source):
- 37 achievements across 6 categories (Victories, Kot, Streaks, Levels, Ranks,
  Veterancy) incl. 7–0 sweeps, kot milestones (1/5/10/25/50/100), win streaks
  (3/5/10/15), level milestones every 5 (5..50), rank floors, games/tricks.
- New AchievementsScreen with category tabs, progress bars, coin + sticker-unlock
  badges, and unlocked/locked states; summary header (unlocked count + coins).
- Some achievements unlock sticker packs: Seven–Zip→Hokm, 25 Kots→Taunts,
  100 Wins→Persian (ownedStickerPackIds now also honors profile.unlocked).
- Prestige titles added: Expert, Professional, Captain, Leader (+ existing).
- Tracks new stat shutoutWins; MatchSummary.shutout (7–0). Profile shows a
  6-item preview + "view all" link.

Leagues: 3 ranked entry tiers — Starter (100, lvl1), Pro (500, lvl10),
Expert (1000, lvl20). Higher league stakes more, so wins/losses swing bigger;
kot bonus now scales to the stake (40%). OnlineLobby shows league cards with
level gating.

Profile photo upload gated to level 25 (client button + server Update guard).

Win animation: PostMatchRewardsModal now shows an animated coins-won count-up
hero on a win.

Verified: dotnet build + tsc + next build clean; sim unlocks 26 achievements
over 500 matches; live server grants first_win/first_kot/shutout_1 and pays
2050 coins on an expert-league shutout+kot win. Images rebuilt on :1500/:1505.

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

src/app/page.tsx

@@ -11,6 +11,7 @@ import { MatchmakingScreen } from "@/components/screens/MatchmakingScreen";
 import { LeaderboardScreen } from "@/components/screens/LeaderboardScreen";
 import { ShopScreen } from "@/components/screens/ShopScreen";
 import { BuyCoinsScreen } from "@/components/screens/BuyCoinsScreen";
+import { AchievementsScreen } from "@/components/screens/AchievementsScreen";
 import { ChatScreen } from "@/components/screens/ChatScreen";
 import { NotificationsScreen } from "@/components/screens/NotificationsScreen";
 import { AuthScreen } from "@/components/screens/AuthScreen";
@@ -168,6 +169,8 @@ function renderScreen(screen: string) {
       return <ShopScreen />;
     case "buycoins":
       return <BuyCoinsScreen />;
+    case "achievements":
+      return <AchievementsScreen />;
     case "chat":
       return <ChatScreen />;
     case "notifications":