Server persistence: EF Core profiles + coin ledger + authoritative rewards

- EF Core (SQLite dev / Postgres prod via config); ProfileRow JSON blob +
  LedgerRow audit; EnsureCreated at startup
- C# Gamification port (ranks/elo/coins/xp/achievements/titles) → server
  computes match rewards; ProfileService (get/update/plan/buyCoins/applyMatch)
- JWT endpoints: profile GET/PUT, plan, coins packs/buy, match/result;
  auth upserts the profile
- Tested end-to-end (buy + ranked win+kot persisted & server-computed)
- Client still mock-backed for now (wiring is the next step)

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

server/src/Hokm.Server/Hokm.Server.csproj

@@ -12,6 +12,8 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="10.0.2" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="10.0.2" />
+    <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="10.0.0" />
   </ItemGroup>
 
 </Project>