feat(bp): /battle_pass/info — service + controller + 3 tests

Also fixes BattlePassRepository.GetActiveSeasonAsync to use client-side
DateTimeOffset filtering (SQLite provider cannot translate DateTimeOffset
comparisons in LINQ WHERE/ORDER BY clauses).

SVSim.Database/Repositories/BattlePass/BattlePassRepository.cs

@@ -18,11 +18,17 @@ public sealed class BattlePassRepository : IBattlePassRepository
 
     public async Task<BattlePassSeasonEntry?> GetActiveSeasonAsync(DateTimeOffset when, CancellationToken ct)
     {
-        return await _db.BattlePassSeasons
+        // Use UtcDateTime for the LINQ comparison so the query translates on both Postgres and
+        // SQLite. DateTimeOffset arithmetic in LINQ isn't supported by the SQLite provider;
+        // DateTime (UTC) is stored and compared as ISO-8601 text which SQLite handles fine.
+        var utcNow = when.UtcDateTime;
+        var candidates = await _db.BattlePassSeasons
             .AsNoTracking()
-            .Where(s => s.StartDate <= when && s.EndDate > when)
+            .ToListAsync(ct);
+        return candidates
+            .Where(s => s.StartDate.UtcDateTime <= utcNow && s.EndDate.UtcDateTime > utcNow)
             .OrderByDescending(s => s.StartDate)
-            .FirstOrDefaultAsync(ct);
+            .FirstOrDefault();
     }
 
     public Task<BattlePassSeasonEntry?> GetSeasonAsync(int seasonId, CancellationToken ct) =>