Crystal synthesis in BuyPremiumAsync is now unconditional: always remove
any crystal entry ApplyAsync may have added, then append the fresh
post-deduction total. Prevents stale on-screen balances when a retroactive
grant also touches crystal (or when no grants fire and the conditional
guard would have been the only crystal entry).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Adds BattlePassSalesPeriodInfoDto, BattlePassProductDto, BattlePassItemListResponse DTOs,
GetItemListAsync on BattlePassService (one product if not premium + CanPurchase, empty if
already premium or off-season), and the /battle_pass/item_list controller action.
2 new integration tests; all 408 pass.
GetOrCreateProgressAsync now persists the new row itself and catches
DbUpdateException on unique-constraint violations — concurrent /info
calls no longer throw 500s. BattlePassService no longer calls
SaveChangesAsync after the get-or-create. FormatWireDate uses a named
JstOffset constant instead of an inline TimeSpan.FromHours(9).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Also fixes BattlePassRepository.GetActiveSeasonAsync to use client-side
DateTimeOffset filtering (SQLite provider cannot translate DateTimeOffset
comparisons in LINQ WHERE/ORDER BY clauses).
