Store XP packs (expensive), winner 2x XP, premium perks

- XP packs in the store (coin-priced, intentionally expensive): xp1 200/5k,
  xp2 600/12k, xp3 1500/25k. Consumable (grant XP, can level up) — server
  ShopBuy handles kind "xp" via an authoritative XpPacks map + Gamification.GrantXp;
  mock mirrors. New shop section + shop.xp/xpHint i18n.
- Every game grants XP and the WINNER earns 2x: matchXp is now
  base*(won?2:1)*leagueFactor (was a flat +80 win bonus). Mirrored server-side.
- Premium (pro) perks: 1.5x XP multiplier (applied in applyMatchResult /
  ApplyMatch by plan), plus animated shimmering gold chat bubbles for your own
  messages (premium-chat CSS; ChatScreen gates on plan).

Verified: tsc + next + dotnet build clean; sim passes; live server — buying xp2
took L1→L3 and deducted 12k coins under the new curve. Images rebuilt :1500/:1505.

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

server/src/Hokm.Server/Profiles/ProfileService.cs

@@ -112,9 +112,30 @@ public class ProfileService
 
     /* ----------------------------- shop ------------------------------- */
 
+    // Coin-priced XP packs (XP is intentionally expensive). Server-authoritative.
+    public static readonly Dictionary<string, (int Price, int Xp)> XpPacks = new()
+    {
+        ["xp1"] = (5000, 200),
+        ["xp2"] = (12000, 600),
+        ["xp3"] = (25000, 1500),
+    };
+
     public async Task<(bool ok, ProfileDto? profile, string error)> ShopBuy(string uid, string kind, string id, int price)
     {
         var p = await GetOrCreate(uid, null);
+
+        // XP packs are consumable (grant XP, may level up) — not added to an owned list.
+        if (kind == "xp")
+        {
+            if (!XpPacks.TryGetValue(id, out var pk)) return (false, p, "bad_kind");
+            if (p.Coins < pk.Price) return (false, p, "insufficient");
+            p.Coins -= pk.Price;
+            Gamification.GrantXp(p, pk.Xp);
+            await Save(p);
+            await Ledger(uid, "xp", -pk.Price, id);
+            return (true, p, "");
+        }
+
         var list = kind switch
         {
             "avatar" => p.OwnedAvatars,