More cosmetics (rank-gated) + steeper level curve capped at 100

Cosmetics — many new variants, the rarer ones gated behind higher ranks:
- Card backs: +midnight/jade/onyx (buy) + crimson/aurora/obsidian/imperial
  (earned by wins/rating up to Master). Card fronts: +sunset/velvet/onyx (buy)
  + goldleaf/crystal/imperial (earned).
- Titles: +marksman, untouchable, sweeper, ruler, platinum_star, diamond_ace,
  immortal, the_one (gated by kots/streak/shutouts/hakem/rating/level/wins),
  mirrored on the server so live games grant them.
- Avatars: list expanded + rank/wins-earned tier (robot/wizard/ninja/king/
  genie/crown) via new ownedAvatarIds(); profile picker shows earned ones,
  shop sells the priced ones.
- Stickers: new Persian-text stamp pack (کوت! / دمت گرم / باریکلا / آخه؟) plus a
  rank-earned Victory pack (بردیم!/حکم) — new inline-SVG art.

Leveling: XP per level now grows (100*l + 15*l²) so each level is harder; higher
leagues grant more XP (×1.5 at 500 stake, ×2 at 1000) so you progress by playing
up. Hard cap at level 100. Mirrored in server Gamification (XpForLevel/MatchXp/
AddXp). Sim now tops out lower (level 20 vs 35 over 500 matches) as intended.

Verified: tsc + next build + dotnet build clean; sim passes; images rebuilt :1500/:1505.

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

src/lib/online/mock-service.ts

@@ -839,12 +839,12 @@ export class MockOnlineService implements OnlineService {
   }
 
   async getShopItems(): Promise<ShopItem[]> {
-    const avatarItems: ShopItem[] = AVATARS.slice(2).map((a, i) => ({
+    const avatarItems: ShopItem[] = AVATARS.filter((a) => (a.price ?? 0) > 0).map((a) => ({
       id: a.id,
       kind: "avatar",
       nameFa: "آواتار",
       nameEn: "Avatar",
-      price: 500 + i * 150,
+      price: a.price!,
       preview: a.emoji,
     }));
     const backItems: ShopItem[] = CARD_BACKS.filter((c) => c.price > 0).map((c) => ({