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.
Also fixes BattlePassRepository.GetActiveSeasonAsync to use client-side
DateTimeOffset filtering (SQLite provider cannot translate DateTimeOffset
comparisons in LINQ WHERE/ORDER BY clauses).
Wire IBattlePassService.GetLevelCurveAsync into LoadController so /load/index
emits the 100-entry battle_pass_level_info dict when levels are seeded.
Also adds BattlePassRepository.ResetLevelCurveCache() to bust the process-level
static cache in tests that seed levels after earlier HTTP calls have primed it
with an empty list, and updates SVSimTestFactory.SeedGlobalsAsync + the stale
Index_surfaces_seeded_globals_after_bootstrap assertion accordingly.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
